gfe-relnote: Delete gfe2_reloadable_flag_quic_writeheaders_excludes_encoder_stream_data flag that has never been rolled out. Protected by gfe2_reloadable_flag_quic_enable_version_draft_25_v3 and gfe2_reloadable_flag_quic_enable_version_draft_27.

cl/308657464 landed earlier today, before I was reminded that
gfe2_reloadable_flag_quic_enable_version_draft_25_v3 and
gfe2_reloadable_flag_quic_enable_version_draft_27 flags have still not been
verified, so that change would not have needed flag protection.  Yay!

PiperOrigin-RevId: 308682978
Change-Id: Ic481d897d700c09caa766518d92068345b88ec4f

quic/core/http/quic_spdy_stream.cc

diff --git a/quic/core/http/quic_spdy_stream.cc b/quic/core/http/quic_spdy_stream.cc
index 5b88ca2..1a83784 100644
--- a/quic/core/http/quic_spdy_stream.cc
+++ b/quic/core/http/quic_spdy_stream.cc
@@ -1127,12 +1127,7 @@
       encoded_headers.size() + encoder_stream_sent_byte_count,
       header_block.TotalBytesUsed());
 
-  if (GetQuicReloadableFlag(quic_writeheaders_excludes_encoder_stream_data)) {
-    QUIC_RELOADABLE_FLAG_COUNT(quic_writeheaders_excludes_encoder_stream_data);
-    return encoded_headers.size();
-  }
-
-  return encoded_headers.size() + encoder_stream_sent_byte_count;
+  return encoded_headers.size();
 }
 
 #undef ENDPOINT  // undef for jumbo builds

quic/core/http/quic_spdy_stream_test.cc

diff --git a/quic/core/http/quic_spdy_stream_test.cc b/quic/core/http/quic_spdy_stream_test.cc
index b0e2c66..cdee5ef 100644
--- a/quic/core/http/quic_spdy_stream_test.cc
+++ b/quic/core/http/quic_spdy_stream_test.cc
@@ -2932,13 +2932,7 @@
       stream_->WriteHeaders(std::move(request_headers), /*fin=*/true, nullptr);
   EXPECT_TRUE(stream_->fin_sent());
 
-  if (GetQuicReloadableFlag(quic_writeheaders_excludes_encoder_stream_data)) {
-    EXPECT_EQ(headers_frame_payload_length, write_headers_return_value);
-  } else {
-    // Return value of WriteHeaders includes length of dynamic table insertions
-    // written on encoder stream.
-    EXPECT_LT(headers_frame_payload_length, write_headers_return_value);
-  }
+  EXPECT_EQ(headers_frame_payload_length, write_headers_return_value);
 }
 
 }  // namespace