Add two missing includes in http2/adapter.

These files would not compile in Chromium otherwise.

PiperOrigin-RevId: 389234271
diff --git a/http2/adapter/oghttp2_adapter_test.cc b/http2/adapter/oghttp2_adapter_test.cc
index 803374e..03b45df 100644
--- a/http2/adapter/oghttp2_adapter_test.cc
+++ b/http2/adapter/oghttp2_adapter_test.cc
@@ -1,5 +1,6 @@
 #include "http2/adapter/oghttp2_adapter.h"
 
+#include "absl/strings/str_join.h"
 #include "http2/adapter/mock_http2_visitor.h"
 #include "http2/adapter/oghttp2_util.h"
 #include "http2/adapter/test_frame_sequence.h"
diff --git a/http2/adapter/test_utils.h b/http2/adapter/test_utils.h
index 0c18cdb..d92617f 100644
--- a/http2/adapter/test_utils.h
+++ b/http2/adapter/test_utils.h
@@ -4,6 +4,7 @@
 #include <string>
 #include <vector>
 
+#include "absl/container/flat_hash_map.h"
 #include "absl/strings/string_view.h"
 #include "http2/adapter/data_source.h"
 #include "http2/adapter/http2_protocol.h"