Avoid SpdyHeaderBlock copy in SpdyStream::OnPushPromiseHeadersReceived().

net/spdy/spdy_session.cc

Index: net/spdy/spdy_session.cc
diff --git a/net/spdy/spdy_session.cc b/net/spdy/spdy_session.cc
index 49338ac571b1d1134c3ff8fe1c61e5492ffb603c..5b25ac55dbeb1cf0ec21c814087b8ff3985d3709 100644
--- a/net/spdy/spdy_session.cc
+++ b/net/spdy/spdy_session.cc
@@ -2236,7 +2236,7 @@ void SpdySession::OnHeaders(SpdyStreamId stream_id,
                             SpdyStreamId parent_stream_id,
                             bool exclusive,
                             bool fin,
-                            const SpdyHeaderBlock& headers) {
+                            SpdyHeaderBlock headers) {
   CHECK(in_io_loop_);
 
   if (net_log().IsCapturing()) {
@@ -2490,7 +2490,7 @@ void SpdySession::OnWindowUpdate(SpdyStreamId stream_id,
 bool SpdySession::TryCreatePushStream(SpdyStreamId stream_id,
                                       SpdyStreamId associated_stream_id,
                                       SpdyPriority priority,
-                                      const SpdyHeaderBlock& headers) {
+                                      SpdyHeaderBlock headers) {
   // Server-initiated streams should have even sequence numbers.
   if ((stream_id & 0x1) != 0) {
     LOG(WARNING) << "Received invalid push stream id " << stream_id;
@@ -2665,7 +2665,7 @@ bool SpdySession::TryCreatePushStream(SpdyStreamId stream_id,
     return false;
   }
 
-  active_it->second.stream->OnPushPromiseHeadersReceived(headers);
+  active_it->second.stream->OnPushPromiseHeadersReceived(std::move(headers));
   DCHECK(active_it->second.stream->IsReservedRemote());
   num_pushed_streams_++;
   return true;
@@ -2673,7 +2673,7 @@ bool SpdySession::TryCreatePushStream(SpdyStreamId stream_id,
 
 void SpdySession::OnPushPromise(SpdyStreamId stream_id,
                                 SpdyStreamId promised_stream_id,
-                                const SpdyHeaderBlock& headers) {
+                                SpdyHeaderBlock headers) {
   CHECK(in_io_loop_);
 
   if (net_log_.IsCapturing()) {
@@ -2684,7 +2684,8 @@ void SpdySession::OnPushPromise(SpdyStreamId stream_id,
 
   // Any priority will do.
   // TODO(baranovich): pass parent stream id priority?
-  if (!TryCreatePushStream(promised_stream_id, stream_id, 0, headers))
+  if (!TryCreatePushStream(promised_stream_id, stream_id, 0,
+                           std::move(headers)))
     return;
 }