Fix QpackDecoder::EncoderStreamRelativeIndexToAbsoluteIndex(), simplify QpackProgressiveDecoder::RequestStreamRelativeIndexToAbsoluteIndex().

gfe-relnote: n/a, change to QUIC v99-only code.  Protected by existing disabled gfe2_reloadable_flag_quic_enable_version_99.
PiperOrigin-RevId: 263413585
Change-Id: I1aab74f6f0d825079779f4d402c9ae1c94a368cd

quic/core/qpack/qpack_decoder.cc

diff --git a/quic/core/qpack/qpack_decoder.cc b/quic/core/qpack/qpack_decoder.cc
index 79db4dd..8e3103c 100644
--- a/quic/core/qpack/qpack_decoder.cc
+++ b/quic/core/qpack/qpack_decoder.cc
@@ -4,8 +4,6 @@
 
 #include "net/third_party/quiche/src/quic/core/qpack/qpack_decoder.h"
 
-#include <limits>
-
 #include "net/third_party/quiche/src/quic/platform/api/quic_logging.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_ptr_util.h"
 
@@ -115,9 +113,7 @@
 bool QpackDecoder::EncoderStreamRelativeIndexToAbsoluteIndex(
     uint64_t relative_index,
     uint64_t* absolute_index) const {
-  if (relative_index == std::numeric_limits<uint64_t>::max() ||
-      relative_index + 1 > std::numeric_limits<uint64_t>::max() -
-                               header_table_.inserted_entry_count()) {
+  if (relative_index >= header_table_.inserted_entry_count()) {
     return false;
   }
 

quic/core/qpack/qpack_decoder_test.cc

diff --git a/quic/core/qpack/qpack_decoder_test.cc b/quic/core/qpack/qpack_decoder_test.cc
index 506d60c..556053b 100644
--- a/quic/core/qpack/qpack_decoder_test.cc
+++ b/quic/core/qpack/qpack_decoder_test.cc
@@ -425,7 +425,7 @@
 
 TEST_P(QpackDecoderTest, EncoderStreamErrorInvalidDynamicTableEntry) {
   EXPECT_CALL(encoder_stream_error_delegate_,
-              OnEncoderStreamError(Eq("Dynamic table entry not found.")));
+              OnEncoderStreamError(Eq("Invalid relative index.")));
 
   DecodeEncoderStreamData(QuicTextUtils::HexDecode(
       "6294e703626172"  // Add literal entry with name "foo" and value "bar".
@@ -436,7 +436,7 @@
 
 TEST_P(QpackDecoderTest, EncoderStreamErrorDuplicateInvalidEntry) {
   EXPECT_CALL(encoder_stream_error_delegate_,
-              OnEncoderStreamError(Eq("Dynamic table entry not found.")));
+              OnEncoderStreamError(Eq("Invalid relative index.")));
 
   DecodeEncoderStreamData(QuicTextUtils::HexDecode(
       "6294e703626172"  // Add literal entry with name "foo" and value "bar".

quic/core/qpack/qpack_progressive_decoder.cc

diff --git a/quic/core/qpack/qpack_progressive_decoder.cc b/quic/core/qpack/qpack_progressive_decoder.cc
index b3c374e..d9449e3 100644
--- a/quic/core/qpack/qpack_progressive_decoder.cc
+++ b/quic/core/qpack/qpack_progressive_decoder.cc
@@ -346,8 +346,7 @@
 bool QpackProgressiveDecoder::RequestStreamRelativeIndexToAbsoluteIndex(
     uint64_t relative_index,
     uint64_t* absolute_index) const {
-  if (relative_index == std::numeric_limits<uint64_t>::max() ||
-      relative_index + 1 > base_) {
+  if (relative_index >= base_) {
     return false;
   }