Remove SETTINGS_NUM_PLACEHOLDERS.

This setting identifier has been removed from the draft at
https://github.com/quicwg/base-drafts/pull/2922.

gfe-relnote: n/a, change to QUIC v99-only code.  Protected by existing disabled gfe2_reloadable_flag_quic_enable_version_99.
PiperOrigin-RevId: 272717598
Change-Id: I49da04545c3dcbe1afd95dcf41845fc0ab6bb04e

quic/core/http/http_constants.h

diff --git a/quic/core/http/http_constants.h b/quic/core/http/http_constants.h
index 9c2c6b5..fbf3069 100644
--- a/quic/core/http/http_constants.h
+++ b/quic/core/http/http_constants.h
@@ -29,7 +29,6 @@
   // Same value as spdy::SETTINGS_MAX_HEADER_LIST_SIZE.
   SETTINGS_MAX_HEADER_LIST_SIZE = 0x06,
   SETTINGS_QPACK_BLOCKED_STREAMS = 0x07,
-  SETTINGS_NUM_PLACEHOLDERS = 0x09,
 };
 
 // Default maximum dynamic table capacity, communicated via

quic/core/http/http_decoder_test.cc

diff --git a/quic/core/http/http_decoder_test.cc b/quic/core/http/http_decoder_test.cc
index 4baf271..c841852 100644
--- a/quic/core/http/http_decoder_test.cc
+++ b/quic/core/http/http_decoder_test.cc
@@ -468,7 +468,7 @@
   std::string input = QuicTextUtils::HexDecode(
       "04"    // type (SETTINGS)
       "07"    // length
-      "03"    // identifier (SETTINGS_NUM_PLACEHOLDERS)
+      "01"    // identifier (SETTINGS_QPACK_MAX_TABLE_CAPACITY)
       "02"    // content
       "06"    // identifier (SETTINGS_MAX_HEADER_LIST_SIZE)
       "05"    // content
@@ -476,7 +476,7 @@
       "04");  // content
 
   SettingsFrame frame;
-  frame.values[3] = 2;
+  frame.values[1] = 2;
   frame.values[6] = 5;
   frame.values[256] = 4;
 

quic/core/http/http_encoder_test.cc

diff --git a/quic/core/http/http_encoder_test.cc b/quic/core/http/http_encoder_test.cc
index eb5e574..43ae7cd 100644
--- a/quic/core/http/http_encoder_test.cc
+++ b/quic/core/http/http_encoder_test.cc
@@ -128,15 +128,15 @@
 
 TEST_F(HttpEncoderTest, SerializeSettingsFrame) {
   SettingsFrame settings;
-  settings.values[3] = 2;
+  settings.values[1] = 2;
   settings.values[6] = 5;
   settings.values[256] = 4;
   char output[] = {// type (SETTINGS)
                    0x04,
                    // length
                    0x07,
-                   // identifier (SETTINGS_NUM_PLACEHOLDERS)
-                   0x03,
+                   // identifier (SETTINGS_QPACK_MAX_TABLE_CAPACITY)
+                   0x01,
                    // content
                    0x02,
                    // identifier (SETTINGS_MAX_HEADER_LIST_SIZE)

quic/core/http/quic_spdy_session.cc

diff --git a/quic/core/http/quic_spdy_session.cc b/quic/core/http/quic_spdy_session.cc
index 07b67e3..736edbf 100644
--- a/quic/core/http/quic_spdy_session.cc
+++ b/quic/core/http/quic_spdy_session.cc
@@ -729,11 +729,6 @@
                       << value;
         qpack_encoder_->SetMaximumBlockedStreams(value);
         break;
-      case SETTINGS_NUM_PLACEHOLDERS:
-        QUIC_DVLOG(1) << "SETTINGS_NUM_PLACEHOLDERS received with value "
-                      << value;
-        // TODO: Support placeholder setting.
-        break;
       default:
         QUIC_DVLOG(1) << "Unknown setting identifier " << id
                       << " received with value " << value;

quic/core/http/spdy_utils.cc

diff --git a/quic/core/http/spdy_utils.cc b/quic/core/http/spdy_utils.cc
index 546b7a8..56d3b19 100644
--- a/quic/core/http/spdy_utils.cc
+++ b/quic/core/http/spdy_utils.cc
@@ -161,7 +161,6 @@
     RETURN_STRING_LITERAL(SETTINGS_QPACK_MAX_TABLE_CAPACITY);
     RETURN_STRING_LITERAL(SETTINGS_MAX_HEADER_LIST_SIZE);
     RETURN_STRING_LITERAL(SETTINGS_QPACK_BLOCKED_STREAMS);
-    RETURN_STRING_LITERAL(SETTINGS_NUM_PLACEHOLDERS);
   }
   return QuicStrCat("UNSUPPORTED_SETTINGS_TYPE(", identifier, ")");
 }