Rename SpdyHeaderBlock to Http2HeaderBlock.

Salvaged from a botched Zwingli attempt:
http://refactor/16032281396283088571 created by go/Zwingli

Tested:
    TAP for global presubmit queue passed after automated deflaking of failures: http://mondo/deflaker/run/ea979a75-dd33-4574-acde-7191db6ea908 http://mondo/deflaker/run/51cec644-aef6-434d-bebd-6cff71dc319b
    http://test/OCL:338336292:BASE:338288991:1603328760683:25591553
PiperOrigin-RevId: 338474585
Change-Id: I3a6fb53e8e3a41386ac9eefc01fb5d32b158d044
diff --git a/quic/tools/quic_simple_server_session.cc b/quic/tools/quic_simple_server_session.cc
index 0637109..72d6259 100644
--- a/quic/tools/quic_simple_server_session.cc
+++ b/quic/tools/quic_simple_server_session.cc
@@ -66,13 +66,13 @@
     const std::list<QuicBackendResponse::ServerPushInfo>& resources,
     QuicStreamId original_stream_id,
     const spdy::SpdyStreamPrecedence& original_precedence,
-    const spdy::SpdyHeaderBlock& original_request_headers) {
+    const spdy::Http2HeaderBlock& original_request_headers) {
   if (!server_push_enabled()) {
     return;
   }
 
   for (const QuicBackendResponse::ServerPushInfo& resource : resources) {
-    spdy::SpdyHeaderBlock headers = SynthesizePushRequestHeaders(
+    spdy::Http2HeaderBlock headers = SynthesizePushRequestHeaders(
         request_url, resource, original_request_headers);
     // TODO(b/136295430): Use sequential push IDs for IETF QUIC.
     auto new_highest_promised_stream_id =
@@ -171,13 +171,13 @@
   }
 }
 
-spdy::SpdyHeaderBlock QuicSimpleServerSession::SynthesizePushRequestHeaders(
+spdy::Http2HeaderBlock QuicSimpleServerSession::SynthesizePushRequestHeaders(
     std::string request_url,
     QuicBackendResponse::ServerPushInfo resource,
-    const spdy::SpdyHeaderBlock& original_request_headers) {
+    const spdy::Http2HeaderBlock& original_request_headers) {
   QuicUrl push_request_url = resource.request_url;
 
-  spdy::SpdyHeaderBlock spdy_headers = original_request_headers.Clone();
+  spdy::Http2HeaderBlock spdy_headers = original_request_headers.Clone();
   // :authority could be different from original request.
   spdy_headers[":authority"] = push_request_url.host();
   spdy_headers[":path"] = push_request_url.path();
@@ -196,7 +196,7 @@
 
 void QuicSimpleServerSession::SendPushPromise(QuicStreamId original_stream_id,
                                               QuicStreamId promised_stream_id,
-                                              spdy::SpdyHeaderBlock headers) {
+                                              spdy::Http2HeaderBlock headers) {
   QUIC_DLOG(INFO) << "stream " << original_stream_id
                   << " send PUSH_PROMISE for promised stream "
                   << promised_stream_id;
@@ -226,7 +226,7 @@
 
     promised_stream->SetPriority(promised_info.precedence);
 
-    spdy::SpdyHeaderBlock request_headers(
+    spdy::Http2HeaderBlock request_headers(
         std::move(promised_info.request_headers));
 
     promised_streams_.pop_front();