diff --git a/build/source_list.bzl b/build/source_list.bzl
index 10a897f..6305574 100644
--- a/build/source_list.bzl
+++ b/build/source_list.bzl
@@ -78,6 +78,7 @@
     "http2/adapter/window_manager.h",
     "http2/core/array_output_buffer.h",
     "http2/core/header_byte_listener_interface.h",
+    "http2/core/http2_constants.h",
     "http2/core/http2_frame_decoder_adapter.h",
     "http2/core/http2_header_block_hpack_listener.h",
     "http2/core/http2_trace_logging.h",
@@ -139,7 +140,6 @@
     "http2/hpack/huffman/huffman_spec_tables.h",
     "http2/hpack/varint/hpack_varint_decoder.h",
     "http2/hpack/varint/hpack_varint_encoder.h",
-    "http2/http2_constants.h",
     "http2/http2_structures.h",
     "quic/core/chlo_extractor.h",
     "quic/core/congestion_control/bandwidth_sampler.h",
@@ -436,6 +436,7 @@
     "http2/adapter/oghttp2_util.cc",
     "http2/adapter/window_manager.cc",
     "http2/core/array_output_buffer.cc",
+    "http2/core/http2_constants.cc",
     "http2/core/http2_frame_decoder_adapter.cc",
     "http2/core/http2_trace_logging.cc",
     "http2/core/recording_headers_handler.cc",
@@ -491,7 +492,6 @@
     "http2/hpack/huffman/huffman_spec_tables.cc",
     "http2/hpack/varint/hpack_varint_decoder.cc",
     "http2/hpack/varint/hpack_varint_encoder.cc",
-    "http2/http2_constants.cc",
     "http2/http2_structures.cc",
     "quic/core/chlo_extractor.cc",
     "quic/core/congestion_control/bandwidth_sampler.cc",
@@ -1121,6 +1121,7 @@
     "http2/adapter/test_utils_test.cc",
     "http2/adapter/window_manager_test.cc",
     "http2/core/array_output_buffer_test.cc",
+    "http2/core/http2_constants_test.cc",
     "http2/core/priority_write_scheduler_test.cc",
     "http2/core/spdy_alt_svc_wire_format_test.cc",
     "http2/core/spdy_frame_builder_test.cc",
@@ -1169,7 +1170,6 @@
     "http2/hpack/varint/hpack_varint_decoder_test.cc",
     "http2/hpack/varint/hpack_varint_encoder_test.cc",
     "http2/hpack/varint/hpack_varint_round_trip_test.cc",
-    "http2/http2_constants_test.cc",
     "http2/http2_structures_test.cc",
     "http2/test_tools/hpack_block_builder_test.cc",
     "http2/test_tools/hpack_example_test.cc",
diff --git a/build/source_list.gni b/build/source_list.gni
index 6fc039b..6eea23b 100644
--- a/build/source_list.gni
+++ b/build/source_list.gni
@@ -78,6 +78,7 @@
     "src/quiche/http2/adapter/window_manager.h",
     "src/quiche/http2/core/array_output_buffer.h",
     "src/quiche/http2/core/header_byte_listener_interface.h",
+    "src/quiche/http2/core/http2_constants.h",
     "src/quiche/http2/core/http2_frame_decoder_adapter.h",
     "src/quiche/http2/core/http2_header_block_hpack_listener.h",
     "src/quiche/http2/core/http2_trace_logging.h",
@@ -139,7 +140,6 @@
     "src/quiche/http2/hpack/huffman/huffman_spec_tables.h",
     "src/quiche/http2/hpack/varint/hpack_varint_decoder.h",
     "src/quiche/http2/hpack/varint/hpack_varint_encoder.h",
-    "src/quiche/http2/http2_constants.h",
     "src/quiche/http2/http2_structures.h",
     "src/quiche/quic/core/chlo_extractor.h",
     "src/quiche/quic/core/congestion_control/bandwidth_sampler.h",
@@ -436,6 +436,7 @@
     "src/quiche/http2/adapter/oghttp2_util.cc",
     "src/quiche/http2/adapter/window_manager.cc",
     "src/quiche/http2/core/array_output_buffer.cc",
+    "src/quiche/http2/core/http2_constants.cc",
     "src/quiche/http2/core/http2_frame_decoder_adapter.cc",
     "src/quiche/http2/core/http2_trace_logging.cc",
     "src/quiche/http2/core/recording_headers_handler.cc",
@@ -491,7 +492,6 @@
     "src/quiche/http2/hpack/huffman/huffman_spec_tables.cc",
     "src/quiche/http2/hpack/varint/hpack_varint_decoder.cc",
     "src/quiche/http2/hpack/varint/hpack_varint_encoder.cc",
-    "src/quiche/http2/http2_constants.cc",
     "src/quiche/http2/http2_structures.cc",
     "src/quiche/quic/core/chlo_extractor.cc",
     "src/quiche/quic/core/congestion_control/bandwidth_sampler.cc",
@@ -1122,6 +1122,7 @@
     "src/quiche/http2/adapter/test_utils_test.cc",
     "src/quiche/http2/adapter/window_manager_test.cc",
     "src/quiche/http2/core/array_output_buffer_test.cc",
+    "src/quiche/http2/core/http2_constants_test.cc",
     "src/quiche/http2/core/priority_write_scheduler_test.cc",
     "src/quiche/http2/core/spdy_alt_svc_wire_format_test.cc",
     "src/quiche/http2/core/spdy_frame_builder_test.cc",
@@ -1170,7 +1171,6 @@
     "src/quiche/http2/hpack/varint/hpack_varint_decoder_test.cc",
     "src/quiche/http2/hpack/varint/hpack_varint_encoder_test.cc",
     "src/quiche/http2/hpack/varint/hpack_varint_round_trip_test.cc",
-    "src/quiche/http2/http2_constants_test.cc",
     "src/quiche/http2/http2_structures_test.cc",
     "src/quiche/http2/test_tools/hpack_block_builder_test.cc",
     "src/quiche/http2/test_tools/hpack_example_test.cc",
diff --git a/build/source_list.json b/build/source_list.json
index 1b46073..9aec0c8 100644
--- a/build/source_list.json
+++ b/build/source_list.json
@@ -77,6 +77,7 @@
     "quiche/http2/adapter/window_manager.h",
     "quiche/http2/core/array_output_buffer.h",
     "quiche/http2/core/header_byte_listener_interface.h",
+    "quiche/http2/core/http2_constants.h",
     "quiche/http2/core/http2_frame_decoder_adapter.h",
     "quiche/http2/core/http2_header_block_hpack_listener.h",
     "quiche/http2/core/http2_trace_logging.h",
@@ -138,7 +139,6 @@
     "quiche/http2/hpack/huffman/huffman_spec_tables.h",
     "quiche/http2/hpack/varint/hpack_varint_decoder.h",
     "quiche/http2/hpack/varint/hpack_varint_encoder.h",
-    "quiche/http2/http2_constants.h",
     "quiche/http2/http2_structures.h",
     "quiche/quic/core/chlo_extractor.h",
     "quiche/quic/core/congestion_control/bandwidth_sampler.h",
@@ -435,6 +435,7 @@
     "quiche/http2/adapter/oghttp2_util.cc",
     "quiche/http2/adapter/window_manager.cc",
     "quiche/http2/core/array_output_buffer.cc",
+    "quiche/http2/core/http2_constants.cc",
     "quiche/http2/core/http2_frame_decoder_adapter.cc",
     "quiche/http2/core/http2_trace_logging.cc",
     "quiche/http2/core/recording_headers_handler.cc",
@@ -490,7 +491,6 @@
     "quiche/http2/hpack/huffman/huffman_spec_tables.cc",
     "quiche/http2/hpack/varint/hpack_varint_decoder.cc",
     "quiche/http2/hpack/varint/hpack_varint_encoder.cc",
-    "quiche/http2/http2_constants.cc",
     "quiche/http2/http2_structures.cc",
     "quiche/quic/core/chlo_extractor.cc",
     "quiche/quic/core/congestion_control/bandwidth_sampler.cc",
@@ -1121,6 +1121,7 @@
     "quiche/http2/adapter/test_utils_test.cc",
     "quiche/http2/adapter/window_manager_test.cc",
     "quiche/http2/core/array_output_buffer_test.cc",
+    "quiche/http2/core/http2_constants_test.cc",
     "quiche/http2/core/priority_write_scheduler_test.cc",
     "quiche/http2/core/spdy_alt_svc_wire_format_test.cc",
     "quiche/http2/core/spdy_frame_builder_test.cc",
@@ -1169,7 +1170,6 @@
     "quiche/http2/hpack/varint/hpack_varint_decoder_test.cc",
     "quiche/http2/hpack/varint/hpack_varint_encoder_test.cc",
     "quiche/http2/hpack/varint/hpack_varint_round_trip_test.cc",
-    "quiche/http2/http2_constants_test.cc",
     "quiche/http2/http2_structures_test.cc",
     "quiche/http2/test_tools/hpack_block_builder_test.cc",
     "quiche/http2/test_tools/hpack_example_test.cc",
diff --git a/quiche/http2/adapter/header_validator.cc b/quiche/http2/adapter/header_validator.cc
index 381491f..6d86858 100644
--- a/quiche/http2/adapter/header_validator.cc
+++ b/quiche/http2/adapter/header_validator.cc
@@ -9,7 +9,7 @@
 #include "absl/strings/numbers.h"
 #include "absl/strings/str_cat.h"
 #include "quiche/http2/adapter/header_validator_base.h"
-#include "quiche/http2/http2_constants.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/common/platform/api/quiche_logging.h"
 
 namespace http2 {
diff --git a/quiche/http2/http2_constants.cc b/quiche/http2/core/http2_constants.cc
similarity index 98%
rename from quiche/http2/http2_constants.cc
rename to quiche/http2/core/http2_constants.cc
index 6792f83..be20fcf 100644
--- a/quiche/http2/http2_constants.cc
+++ b/quiche/http2/core/http2_constants.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "quiche/http2/http2_constants.h"
+#include "quiche/http2/core/http2_constants.h"
 
 #include <string>
 
diff --git a/quiche/http2/http2_constants.h b/quiche/http2/core/http2_constants.h
similarity index 98%
rename from quiche/http2/http2_constants.h
rename to quiche/http2/core/http2_constants.h
index f4034bd..c3fa455 100644
--- a/quiche/http2/http2_constants.h
+++ b/quiche/http2/core/http2_constants.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef QUICHE_HTTP2_HTTP2_CONSTANTS_H_
-#define QUICHE_HTTP2_HTTP2_CONSTANTS_H_
+#ifndef QUICHE_HTTP2_CORE_HTTP2_CONSTANTS_H_
+#define QUICHE_HTTP2_CORE_HTTP2_CONSTANTS_H_
 
 // Constants from the HTTP/2 spec, RFC 7540, and associated helper functions.
 
@@ -267,4 +267,4 @@
 
 }  // namespace http2
 
-#endif  // QUICHE_HTTP2_HTTP2_CONSTANTS_H_
+#endif  // QUICHE_HTTP2_CORE_HTTP2_CONSTANTS_H_
diff --git a/quiche/http2/http2_constants_test.cc b/quiche/http2/core/http2_constants_test.cc
similarity index 99%
rename from quiche/http2/http2_constants_test.cc
rename to quiche/http2/core/http2_constants_test.cc
index 8478ae6..757d7e6 100644
--- a/quiche/http2/http2_constants_test.cc
+++ b/quiche/http2/core/http2_constants_test.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "quiche/http2/http2_constants.h"
+#include "quiche/http2/core/http2_constants.h"
 
 #include "quiche/common/platform/api/quiche_test.h"
 
diff --git a/quiche/http2/core/http2_frame_decoder_adapter.cc b/quiche/http2/core/http2_frame_decoder_adapter.cc
index 38420ee..d73f8fc 100644
--- a/quiche/http2/core/http2_frame_decoder_adapter.cc
+++ b/quiche/http2/core/http2_frame_decoder_adapter.cc
@@ -17,6 +17,7 @@
 #include <string>
 
 #include "absl/strings/string_view.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/core/spdy_alt_svc_wire_format.h"
 #include "quiche/http2/core/spdy_headers_handler_interface.h"
 #include "quiche/http2/core/spdy_protocol.h"
@@ -26,7 +27,6 @@
 #include "quiche/http2/hpack/decoder/hpack_decoding_error.h"
 #include "quiche/http2/hpack/hpack_decoder_adapter.h"
 #include "quiche/http2/hpack/hpack_header_table.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_bug_tracker.h"
 #include "quiche/common/platform/api/quiche_logging.h"
diff --git a/quiche/http2/core/http2_frame_decoder_adapter.h b/quiche/http2/core/http2_frame_decoder_adapter.h
index 54c041b..a273a51 100644
--- a/quiche/http2/core/http2_frame_decoder_adapter.h
+++ b/quiche/http2/core/http2_frame_decoder_adapter.h
@@ -13,6 +13,7 @@
 #include <string>
 
 #include "absl/strings/string_view.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/core/spdy_alt_svc_wire_format.h"
 #include "quiche/http2/core/spdy_headers_handler_interface.h"
 #include "quiche/http2/core/spdy_protocol.h"
@@ -20,7 +21,6 @@
 #include "quiche/http2/decoder/http2_frame_decoder.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
 #include "quiche/http2/hpack/hpack_decoder_adapter.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_export.h"
 
diff --git a/quiche/http2/decoder/decode_http2_structures.cc b/quiche/http2/decoder/decode_http2_structures.cc
index 1730a21..5b0dc91 100644
--- a/quiche/http2/decoder/decode_http2_structures.cc
+++ b/quiche/http2/decoder/decode_http2_structures.cc
@@ -7,8 +7,8 @@
 #include <cstdint>
 #include <cstring>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/common/platform/api/quiche_logging.h"
 
 namespace http2 {
diff --git a/quiche/http2/decoder/decode_http2_structures_test.cc b/quiche/http2/decoder/decode_http2_structures_test.cc
index 61413f3..155ccaa 100644
--- a/quiche/http2/decoder/decode_http2_structures_test.cc
+++ b/quiche/http2/decoder/decode_http2_structures_test.cc
@@ -12,9 +12,9 @@
 #include <string>
 
 #include "absl/strings/string_view.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/decode_status.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/test_tools/http2_frame_builder.h"
 #include "quiche/http2/test_tools/http2_random.h"
 #include "quiche/http2/test_tools/http2_structures_test_util.h"
diff --git a/quiche/http2/decoder/frame_decoder_state.h b/quiche/http2/decoder/frame_decoder_state.h
index 39757da..c643ead 100644
--- a/quiche/http2/decoder/frame_decoder_state.h
+++ b/quiche/http2/decoder/frame_decoder_state.h
@@ -16,11 +16,11 @@
 
 #include <cstdint>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/decode_status.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
 #include "quiche/http2/decoder/http2_structure_decoder.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_export.h"
 #include "quiche/common/platform/api/quiche_logging.h"
diff --git a/quiche/http2/decoder/http2_frame_decoder.cc b/quiche/http2/decoder/http2_frame_decoder.cc
index 8748603..57c3e13 100644
--- a/quiche/http2/decoder/http2_frame_decoder.cc
+++ b/quiche/http2/decoder/http2_frame_decoder.cc
@@ -6,9 +6,9 @@
 
 #include <ostream>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_status.h"
 #include "quiche/http2/hpack/varint/hpack_varint_decoder.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/common/platform/api/quiche_bug_tracker.h"
 #include "quiche/common/platform/api/quiche_logging.h"
 
diff --git a/quiche/http2/decoder/http2_frame_decoder_listener.h b/quiche/http2/decoder/http2_frame_decoder_listener.h
index 0a98b3d..9408eab 100644
--- a/quiche/http2/decoder/http2_frame_decoder_listener.h
+++ b/quiche/http2/decoder/http2_frame_decoder_listener.h
@@ -31,7 +31,7 @@
 #include <cstdint>
 #include <type_traits>
 
-#include "quiche/http2/http2_constants.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_export.h"
 
diff --git a/quiche/http2/decoder/http2_frame_decoder_test.cc b/quiche/http2/decoder/http2_frame_decoder_test.cc
index c884e68..a6dbf1a 100644
--- a/quiche/http2/decoder/http2_frame_decoder_test.cc
+++ b/quiche/http2/decoder/http2_frame_decoder_test.cc
@@ -11,7 +11,7 @@
 #include <vector>
 
 #include "absl/strings/string_view.h"
-#include "quiche/http2/http2_constants.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/test_tools/frame_parts.h"
 #include "quiche/http2/test_tools/frame_parts_collector_listener.h"
 #include "quiche/http2/test_tools/http2_random.h"
diff --git a/quiche/http2/decoder/http2_structure_decoder_remaining_payload_test.cc b/quiche/http2/decoder/http2_structure_decoder_remaining_payload_test.cc
index 6613b71..6e240a5 100644
--- a/quiche/http2/decoder/http2_structure_decoder_remaining_payload_test.cc
+++ b/quiche/http2/decoder/http2_structure_decoder_remaining_payload_test.cc
@@ -12,10 +12,10 @@
 
 #include "absl/flags/flag.h"
 #include "absl/strings/string_view.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/decode_status.h"
 #include "quiche/http2/decoder/http2_structure_decoder.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/http2/test_tools/http2_structure_decoder_test_util.h"
 #include "quiche/http2/test_tools/http2_structures_test_util.h"
diff --git a/quiche/http2/decoder/http2_structure_decoder_test.cc b/quiche/http2/decoder/http2_structure_decoder_test.cc
index 0b2d0c8..324ff09 100644
--- a/quiche/http2/decoder/http2_structure_decoder_test.cc
+++ b/quiche/http2/decoder/http2_structure_decoder_test.cc
@@ -25,9 +25,9 @@
 #include <utility>
 
 #include "absl/strings/string_view.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/decode_status.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/test_tools/http2_frame_builder.h"
 #include "quiche/http2/test_tools/http2_structures_test_util.h"
 #include "quiche/http2/test_tools/random_decoder_test_base.h"
diff --git a/quiche/http2/decoder/payload_decoders/altsvc_payload_decoder.cc b/quiche/http2/decoder/payload_decoders/altsvc_payload_decoder.cc
index 67fc7b7..e69507a 100644
--- a/quiche/http2/decoder/payload_decoders/altsvc_payload_decoder.cc
+++ b/quiche/http2/decoder/payload_decoders/altsvc_payload_decoder.cc
@@ -9,9 +9,9 @@
 #include <ostream>
 
 #include "absl/base/macros.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_bug_tracker.h"
 #include "quiche/common/platform/api/quiche_logging.h"
diff --git a/quiche/http2/decoder/payload_decoders/altsvc_payload_decoder_test.cc b/quiche/http2/decoder/payload_decoders/altsvc_payload_decoder_test.cc
index f41934c..cd53de6 100644
--- a/quiche/http2/decoder/payload_decoders/altsvc_payload_decoder_test.cc
+++ b/quiche/http2/decoder/payload_decoders/altsvc_payload_decoder_test.cc
@@ -9,8 +9,8 @@
 #include <string>
 #include <tuple>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/test_tools/frame_parts.h"
 #include "quiche/http2/test_tools/frame_parts_collector.h"
 #include "quiche/http2/test_tools/http2_frame_builder.h"
diff --git a/quiche/http2/decoder/payload_decoders/continuation_payload_decoder.cc b/quiche/http2/decoder/payload_decoders/continuation_payload_decoder.cc
index 0ed64a9..fabccd8 100644
--- a/quiche/http2/decoder/payload_decoders/continuation_payload_decoder.cc
+++ b/quiche/http2/decoder/payload_decoders/continuation_payload_decoder.cc
@@ -6,9 +6,9 @@
 
 #include <stddef.h>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_logging.h"
 
diff --git a/quiche/http2/decoder/payload_decoders/continuation_payload_decoder_test.cc b/quiche/http2/decoder/payload_decoders/continuation_payload_decoder_test.cc
index e7aec65..309a8fc 100644
--- a/quiche/http2/decoder/payload_decoders/continuation_payload_decoder_test.cc
+++ b/quiche/http2/decoder/payload_decoders/continuation_payload_decoder_test.cc
@@ -9,8 +9,8 @@
 #include <string>
 #include <type_traits>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/http2/test_tools/frame_parts.h"
 #include "quiche/http2/test_tools/frame_parts_collector.h"
diff --git a/quiche/http2/decoder/payload_decoders/data_payload_decoder.cc b/quiche/http2/decoder/payload_decoders/data_payload_decoder.cc
index 1383787..6f532d3 100644
--- a/quiche/http2/decoder/payload_decoders/data_payload_decoder.cc
+++ b/quiche/http2/decoder/payload_decoders/data_payload_decoder.cc
@@ -9,9 +9,9 @@
 #include <ostream>
 
 #include "absl/base/macros.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_bug_tracker.h"
 #include "quiche/common/platform/api/quiche_logging.h"
diff --git a/quiche/http2/decoder/payload_decoders/data_payload_decoder_test.cc b/quiche/http2/decoder/payload_decoders/data_payload_decoder_test.cc
index bbd4913..2adabfd 100644
--- a/quiche/http2/decoder/payload_decoders/data_payload_decoder_test.cc
+++ b/quiche/http2/decoder/payload_decoders/data_payload_decoder_test.cc
@@ -8,8 +8,8 @@
 
 #include <string>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/http2/test_tools/frame_parts.h"
 #include "quiche/http2/test_tools/frame_parts_collector.h"
diff --git a/quiche/http2/decoder/payload_decoders/goaway_payload_decoder.cc b/quiche/http2/decoder/payload_decoders/goaway_payload_decoder.cc
index 2ea52d9..c25e6d3 100644
--- a/quiche/http2/decoder/payload_decoders/goaway_payload_decoder.cc
+++ b/quiche/http2/decoder/payload_decoders/goaway_payload_decoder.cc
@@ -9,9 +9,9 @@
 #include <ostream>
 
 #include "absl/base/macros.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_bug_tracker.h"
 #include "quiche/common/platform/api/quiche_logging.h"
diff --git a/quiche/http2/decoder/payload_decoders/goaway_payload_decoder_test.cc b/quiche/http2/decoder/payload_decoders/goaway_payload_decoder_test.cc
index 78f44d1..60c865a 100644
--- a/quiche/http2/decoder/payload_decoders/goaway_payload_decoder_test.cc
+++ b/quiche/http2/decoder/payload_decoders/goaway_payload_decoder_test.cc
@@ -8,8 +8,8 @@
 
 #include <string>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/test_tools/frame_parts.h"
 #include "quiche/http2/test_tools/frame_parts_collector.h"
 #include "quiche/http2/test_tools/http2_frame_builder.h"
diff --git a/quiche/http2/decoder/payload_decoders/headers_payload_decoder.cc b/quiche/http2/decoder/payload_decoders/headers_payload_decoder.cc
index 123c354..54624c5 100644
--- a/quiche/http2/decoder/payload_decoders/headers_payload_decoder.cc
+++ b/quiche/http2/decoder/payload_decoders/headers_payload_decoder.cc
@@ -9,9 +9,9 @@
 #include <ostream>
 
 #include "absl/base/macros.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_bug_tracker.h"
 #include "quiche/common/platform/api/quiche_logging.h"
diff --git a/quiche/http2/decoder/payload_decoders/headers_payload_decoder_test.cc b/quiche/http2/decoder/payload_decoders/headers_payload_decoder_test.cc
index f6f9af1..a182707 100644
--- a/quiche/http2/decoder/payload_decoders/headers_payload_decoder_test.cc
+++ b/quiche/http2/decoder/payload_decoders/headers_payload_decoder_test.cc
@@ -8,8 +8,8 @@
 
 #include <string>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/test_tools/frame_parts.h"
 #include "quiche/http2/test_tools/frame_parts_collector.h"
 #include "quiche/http2/test_tools/http2_frame_builder.h"
diff --git a/quiche/http2/decoder/payload_decoders/ping_payload_decoder.cc b/quiche/http2/decoder/payload_decoders/ping_payload_decoder.cc
index c700ac2..56ef4de 100644
--- a/quiche/http2/decoder/payload_decoders/ping_payload_decoder.cc
+++ b/quiche/http2/decoder/payload_decoders/ping_payload_decoder.cc
@@ -4,8 +4,8 @@
 
 #include "quiche/http2/decoder/payload_decoders/ping_payload_decoder.h"
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/common/platform/api/quiche_logging.h"
 
 namespace http2 {
diff --git a/quiche/http2/decoder/payload_decoders/ping_payload_decoder_test.cc b/quiche/http2/decoder/payload_decoders/ping_payload_decoder_test.cc
index dba03b1..1966542 100644
--- a/quiche/http2/decoder/payload_decoders/ping_payload_decoder_test.cc
+++ b/quiche/http2/decoder/payload_decoders/ping_payload_decoder_test.cc
@@ -6,8 +6,8 @@
 
 #include <stddef.h>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/test_tools/frame_parts.h"
 #include "quiche/http2/test_tools/frame_parts_collector.h"
 #include "quiche/http2/test_tools/http2_frame_builder.h"
diff --git a/quiche/http2/decoder/payload_decoders/priority_payload_decoder.cc b/quiche/http2/decoder/payload_decoders/priority_payload_decoder.cc
index 1a5a57b..30e12e5 100644
--- a/quiche/http2/decoder/payload_decoders/priority_payload_decoder.cc
+++ b/quiche/http2/decoder/payload_decoders/priority_payload_decoder.cc
@@ -4,9 +4,9 @@
 
 #include "quiche/http2/decoder/payload_decoders/priority_payload_decoder.h"
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_logging.h"
 
diff --git a/quiche/http2/decoder/payload_decoders/priority_payload_decoder_test.cc b/quiche/http2/decoder/payload_decoders/priority_payload_decoder_test.cc
index 573433b..d3bbfe6 100644
--- a/quiche/http2/decoder/payload_decoders/priority_payload_decoder_test.cc
+++ b/quiche/http2/decoder/payload_decoders/priority_payload_decoder_test.cc
@@ -6,8 +6,8 @@
 
 #include <stddef.h>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/test_tools/frame_parts.h"
 #include "quiche/http2/test_tools/frame_parts_collector.h"
 #include "quiche/http2/test_tools/http2_frame_builder.h"
diff --git a/quiche/http2/decoder/payload_decoders/priority_update_payload_decoder.cc b/quiche/http2/decoder/payload_decoders/priority_update_payload_decoder.cc
index d07c183..7648f86 100644
--- a/quiche/http2/decoder/payload_decoders/priority_update_payload_decoder.cc
+++ b/quiche/http2/decoder/payload_decoders/priority_update_payload_decoder.cc
@@ -9,9 +9,9 @@
 #include <ostream>
 
 #include "absl/base/macros.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_bug_tracker.h"
 #include "quiche/common/platform/api/quiche_logging.h"
diff --git a/quiche/http2/decoder/payload_decoders/priority_update_payload_decoder_test.cc b/quiche/http2/decoder/payload_decoders/priority_update_payload_decoder_test.cc
index 14f3557..f78285b 100644
--- a/quiche/http2/decoder/payload_decoders/priority_update_payload_decoder_test.cc
+++ b/quiche/http2/decoder/payload_decoders/priority_update_payload_decoder_test.cc
@@ -8,8 +8,8 @@
 
 #include <string>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/test_tools/frame_parts.h"
 #include "quiche/http2/test_tools/frame_parts_collector.h"
 #include "quiche/http2/test_tools/http2_frame_builder.h"
diff --git a/quiche/http2/decoder/payload_decoders/push_promise_payload_decoder.cc b/quiche/http2/decoder/payload_decoders/push_promise_payload_decoder.cc
index 60da74e..d5d843b 100644
--- a/quiche/http2/decoder/payload_decoders/push_promise_payload_decoder.cc
+++ b/quiche/http2/decoder/payload_decoders/push_promise_payload_decoder.cc
@@ -9,9 +9,9 @@
 #include <ostream>
 
 #include "absl/base/macros.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_bug_tracker.h"
 #include "quiche/common/platform/api/quiche_logging.h"
diff --git a/quiche/http2/decoder/payload_decoders/push_promise_payload_decoder_test.cc b/quiche/http2/decoder/payload_decoders/push_promise_payload_decoder_test.cc
index 2ea5e62..4983d0c 100644
--- a/quiche/http2/decoder/payload_decoders/push_promise_payload_decoder_test.cc
+++ b/quiche/http2/decoder/payload_decoders/push_promise_payload_decoder_test.cc
@@ -8,8 +8,8 @@
 
 #include <string>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/test_tools/frame_parts.h"
 #include "quiche/http2/test_tools/frame_parts_collector.h"
 #include "quiche/http2/test_tools/http2_frame_builder.h"
diff --git a/quiche/http2/decoder/payload_decoders/rst_stream_payload_decoder.cc b/quiche/http2/decoder/payload_decoders/rst_stream_payload_decoder.cc
index 27d410c..60af02a 100644
--- a/quiche/http2/decoder/payload_decoders/rst_stream_payload_decoder.cc
+++ b/quiche/http2/decoder/payload_decoders/rst_stream_payload_decoder.cc
@@ -4,9 +4,9 @@
 
 #include "quiche/http2/decoder/payload_decoders/rst_stream_payload_decoder.h"
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_logging.h"
 
diff --git a/quiche/http2/decoder/payload_decoders/rst_stream_payload_decoder_test.cc b/quiche/http2/decoder/payload_decoders/rst_stream_payload_decoder_test.cc
index 999d7d0..667b6f0 100644
--- a/quiche/http2/decoder/payload_decoders/rst_stream_payload_decoder_test.cc
+++ b/quiche/http2/decoder/payload_decoders/rst_stream_payload_decoder_test.cc
@@ -6,8 +6,8 @@
 
 #include <stddef.h>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/test_tools/frame_parts.h"
 #include "quiche/http2/test_tools/frame_parts_collector.h"
 #include "quiche/http2/test_tools/http2_constants_test_util.h"
diff --git a/quiche/http2/decoder/payload_decoders/settings_payload_decoder.cc b/quiche/http2/decoder/payload_decoders/settings_payload_decoder.cc
index 0ba328f..20d0e2b 100644
--- a/quiche/http2/decoder/payload_decoders/settings_payload_decoder.cc
+++ b/quiche/http2/decoder/payload_decoders/settings_payload_decoder.cc
@@ -4,9 +4,9 @@
 
 #include "quiche/http2/decoder/payload_decoders/settings_payload_decoder.h"
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_logging.h"
 
diff --git a/quiche/http2/decoder/payload_decoders/settings_payload_decoder_test.cc b/quiche/http2/decoder/payload_decoders/settings_payload_decoder_test.cc
index 3533fd4..2e4ee6f 100644
--- a/quiche/http2/decoder/payload_decoders/settings_payload_decoder_test.cc
+++ b/quiche/http2/decoder/payload_decoders/settings_payload_decoder_test.cc
@@ -8,8 +8,8 @@
 
 #include <vector>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/test_tools/frame_parts.h"
 #include "quiche/http2/test_tools/frame_parts_collector.h"
 #include "quiche/http2/test_tools/http2_constants_test_util.h"
diff --git a/quiche/http2/decoder/payload_decoders/unknown_payload_decoder.cc b/quiche/http2/decoder/payload_decoders/unknown_payload_decoder.cc
index bb8dae7..1da41fd 100644
--- a/quiche/http2/decoder/payload_decoders/unknown_payload_decoder.cc
+++ b/quiche/http2/decoder/payload_decoders/unknown_payload_decoder.cc
@@ -6,9 +6,9 @@
 
 #include <stddef.h>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_logging.h"
 
diff --git a/quiche/http2/decoder/payload_decoders/unknown_payload_decoder_test.cc b/quiche/http2/decoder/payload_decoders/unknown_payload_decoder_test.cc
index 47f89b7..9832806 100644
--- a/quiche/http2/decoder/payload_decoders/unknown_payload_decoder_test.cc
+++ b/quiche/http2/decoder/payload_decoders/unknown_payload_decoder_test.cc
@@ -9,8 +9,8 @@
 #include <string>
 #include <type_traits>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/http2/test_tools/frame_parts.h"
 #include "quiche/http2/test_tools/frame_parts_collector.h"
diff --git a/quiche/http2/decoder/payload_decoders/window_update_payload_decoder.cc b/quiche/http2/decoder/payload_decoders/window_update_payload_decoder.cc
index 4174df8..168b5c8 100644
--- a/quiche/http2/decoder/payload_decoders/window_update_payload_decoder.cc
+++ b/quiche/http2/decoder/payload_decoders/window_update_payload_decoder.cc
@@ -4,10 +4,10 @@
 
 #include "quiche/http2/decoder/payload_decoders/window_update_payload_decoder.h"
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/decode_http2_structures.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_logging.h"
 
diff --git a/quiche/http2/decoder/payload_decoders/window_update_payload_decoder_test.cc b/quiche/http2/decoder/payload_decoders/window_update_payload_decoder_test.cc
index 6dd8205..2798494 100644
--- a/quiche/http2/decoder/payload_decoders/window_update_payload_decoder_test.cc
+++ b/quiche/http2/decoder/payload_decoders/window_update_payload_decoder_test.cc
@@ -6,8 +6,8 @@
 
 #include <stddef.h>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/test_tools/frame_parts.h"
 #include "quiche/http2/test_tools/frame_parts_collector.h"
 #include "quiche/http2/test_tools/http2_frame_builder.h"
diff --git a/quiche/http2/hpack/decoder/hpack_decoder_state.cc b/quiche/http2/hpack/decoder/hpack_decoder_state.cc
index f28c929..34659d8 100644
--- a/quiche/http2/hpack/decoder/hpack_decoder_state.cc
+++ b/quiche/http2/hpack/decoder/hpack_decoder_state.cc
@@ -7,7 +7,7 @@
 #include <string>
 #include <utility>
 
-#include "quiche/http2/http2_constants.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/common/platform/api/quiche_logging.h"
 
 namespace http2 {
diff --git a/quiche/http2/hpack/decoder/hpack_decoder_state_test.cc b/quiche/http2/hpack/decoder/hpack_decoder_state_test.cc
index 12df0be..fe97c14 100644
--- a/quiche/http2/hpack/decoder/hpack_decoder_state_test.cc
+++ b/quiche/http2/hpack/decoder/hpack_decoder_state_test.cc
@@ -10,8 +10,8 @@
 #include <vector>
 
 #include "absl/strings/string_view.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/hpack/http2_hpack_constants.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/test_tools/verify_macros.h"
 #include "quiche/common/platform/api/quiche_logging.h"
 #include "quiche/common/platform/api/quiche_test.h"
diff --git a/quiche/http2/hpack/decoder/hpack_decoder_tables.h b/quiche/http2/hpack/decoder/hpack_decoder_tables.h
index 38f665d..7266d2b 100644
--- a/quiche/http2/hpack/decoder/hpack_decoder_tables.h
+++ b/quiche/http2/hpack/decoder/hpack_decoder_tables.h
@@ -24,7 +24,7 @@
 #include <utility>
 #include <vector>
 
-#include "quiche/http2/http2_constants.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/common/platform/api/quiche_export.h"
 #include "quiche/common/quiche_circular_deque.h"
 
diff --git a/quiche/http2/hpack/decoder/hpack_decoder_test.cc b/quiche/http2/hpack/decoder/hpack_decoder_test.cc
index 2b16d82..3221e2c 100644
--- a/quiche/http2/hpack/decoder/hpack_decoder_test.cc
+++ b/quiche/http2/hpack/decoder/hpack_decoder_test.cc
@@ -11,12 +11,12 @@
 #include <utility>
 #include <vector>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/hpack/decoder/hpack_decoder_listener.h"
 #include "quiche/http2/hpack/decoder/hpack_decoder_state.h"
 #include "quiche/http2/hpack/decoder/hpack_decoder_tables.h"
 #include "quiche/http2/hpack/http2_hpack_constants.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/test_tools/hpack_block_builder.h"
 #include "quiche/http2/test_tools/hpack_example.h"
 #include "quiche/http2/test_tools/http2_random.h"
diff --git a/quiche/http2/http2_structures.h b/quiche/http2/http2_structures.h
index 3e1e4dd..f8af6a0 100644
--- a/quiche/http2/http2_structures.h
+++ b/quiche/http2/http2_structures.h
@@ -31,7 +31,7 @@
 #include <ostream>
 #include <string>
 
-#include "quiche/http2/http2_constants.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/common/platform/api/quiche_export.h"
 #include "quiche/common/platform/api/quiche_logging.h"
 
diff --git a/quiche/http2/test_tools/frame_parts.h b/quiche/http2/test_tools/frame_parts.h
index 9ae5185..9232fa4 100644
--- a/quiche/http2/test_tools/frame_parts.h
+++ b/quiche/http2/test_tools/frame_parts.h
@@ -18,8 +18,8 @@
 #include <vector>
 
 #include "absl/strings/string_view.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_export.h"
 #include "quiche/common/platform/api/quiche_logging.h"
diff --git a/quiche/http2/test_tools/frame_parts_collector_listener.h b/quiche/http2/test_tools/frame_parts_collector_listener.h
index a7412d4..e3353f0 100644
--- a/quiche/http2/test_tools/frame_parts_collector_listener.h
+++ b/quiche/http2/test_tools/frame_parts_collector_listener.h
@@ -16,8 +16,8 @@
 
 #include <cstdint>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/http2/test_tools/frame_parts_collector.h"
 #include "quiche/common/platform/api/quiche_export.h"
diff --git a/quiche/http2/test_tools/http2_constants_test_util.h b/quiche/http2/test_tools/http2_constants_test_util.h
index 20edc8d..7f36418 100644
--- a/quiche/http2/test_tools/http2_constants_test_util.h
+++ b/quiche/http2/test_tools/http2_constants_test_util.h
@@ -8,7 +8,7 @@
 #include <cstdint>
 #include <vector>
 
-#include "quiche/http2/http2_constants.h"
+#include "quiche/http2/core/http2_constants.h"
 
 namespace http2 {
 namespace test {
diff --git a/quiche/http2/test_tools/http2_frame_builder.h b/quiche/http2/test_tools/http2_frame_builder.h
index 8ff1916..394d513 100644
--- a/quiche/http2/test_tools/http2_frame_builder.h
+++ b/quiche/http2/test_tools/http2_frame_builder.h
@@ -19,7 +19,7 @@
 #include <string>
 
 #include "absl/strings/string_view.h"
-#include "quiche/http2/http2_constants.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_export.h"
 
diff --git a/quiche/http2/test_tools/http2_frame_decoder_listener_test_util.cc b/quiche/http2/test_tools/http2_frame_decoder_listener_test_util.cc
index fea56f2..5966236 100644
--- a/quiche/http2/test_tools/http2_frame_decoder_listener_test_util.cc
+++ b/quiche/http2/test_tools/http2_frame_decoder_listener_test_util.cc
@@ -4,8 +4,8 @@
 
 #include "quiche/http2/test_tools/http2_frame_decoder_listener_test_util.h"
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_logging.h"
 #include "quiche/common/platform/api/quiche_test.h"
diff --git a/quiche/http2/test_tools/http2_frame_decoder_listener_test_util.h b/quiche/http2/test_tools/http2_frame_decoder_listener_test_util.h
index db341ce..4b811cf 100644
--- a/quiche/http2/test_tools/http2_frame_decoder_listener_test_util.h
+++ b/quiche/http2/test_tools/http2_frame_decoder_listener_test_util.h
@@ -9,8 +9,8 @@
 
 #include <cstdint>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/common/platform/api/quiche_export.h"
 
diff --git a/quiche/http2/test_tools/http2_structures_test_util.cc b/quiche/http2/test_tools/http2_structures_test_util.cc
index 09bf1ee..5642acf 100644
--- a/quiche/http2/test_tools/http2_structures_test_util.cc
+++ b/quiche/http2/test_tools/http2_structures_test_util.cc
@@ -6,7 +6,7 @@
 
 #include <cstdint>
 
-#include "quiche/http2/http2_constants.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/http2/test_tools/http2_constants_test_util.h"
 #include "quiche/http2/test_tools/http2_random.h"
diff --git a/quiche/http2/test_tools/payload_decoder_base_test_util.h b/quiche/http2/test_tools/payload_decoder_base_test_util.h
index 937cea8..dc449fb 100644
--- a/quiche/http2/test_tools/payload_decoder_base_test_util.h
+++ b/quiche/http2/test_tools/payload_decoder_base_test_util.h
@@ -12,11 +12,11 @@
 #include <string>
 
 #include "absl/strings/string_view.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/decode_status.h"
 #include "quiche/http2/decoder/frame_decoder_state.h"
 #include "quiche/http2/decoder/http2_frame_decoder_listener.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/http2_structures.h"
 #include "quiche/http2/test_tools/frame_parts.h"
 #include "quiche/http2/test_tools/http2_constants_test_util.h"
diff --git a/quiche/http2/test_tools/random_decoder_test_base.cc b/quiche/http2/test_tools/random_decoder_test_base.cc
index b3439e9..f17deca 100644
--- a/quiche/http2/test_tools/random_decoder_test_base.cc
+++ b/quiche/http2/test_tools/random_decoder_test_base.cc
@@ -9,9 +9,9 @@
 #include <algorithm>
 #include <memory>
 
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/decoder/decode_buffer.h"
 #include "quiche/http2/decoder/decode_status.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/http2/test_tools/verify_macros.h"
 #include "quiche/common/platform/api/quiche_logging.h"
 #include "quiche/common/platform/api/quiche_test.h"
diff --git a/quiche/quic/core/http/http_decoder.cc b/quiche/quic/core/http/http_decoder.cc
index 9e0385e..4b90a59 100644
--- a/quiche/quic/core/http/http_decoder.cc
+++ b/quiche/quic/core/http/http_decoder.cc
@@ -11,7 +11,7 @@
 
 #include "absl/base/attributes.h"
 #include "absl/strings/string_view.h"
-#include "quiche/http2/http2_constants.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/quic/core/http/http_frames.h"
 #include "quiche/quic/core/quic_data_reader.h"
 #include "quiche/quic/core/quic_error_codes.h"
diff --git a/quiche/quic/core/http/quic_spdy_stream.cc b/quiche/quic/core/http/quic_spdy_stream.cc
index ba0d33c..7701521 100644
--- a/quiche/quic/core/http/quic_spdy_stream.cc
+++ b/quiche/quic/core/http/quic_spdy_stream.cc
@@ -15,8 +15,8 @@
 #include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"
 #include "quiche/http2/adapter/header_validator.h"
+#include "quiche/http2/core/http2_constants.h"
 #include "quiche/http2/core/spdy_protocol.h"
-#include "quiche/http2/http2_constants.h"
 #include "quiche/quic/core/http/http_constants.h"
 #include "quiche/quic/core/http/http_decoder.h"
 #include "quiche/quic/core/http/http_frames.h"