Fix a potential infinite loop in HttpStreamFactoryImpl when a new SpdySession is established

net/http/http_stream_factory_impl.cc

Index: net/http/http_stream_factory_impl.cc
diff --git a/net/http/http_stream_factory_impl.cc b/net/http/http_stream_factory_impl.cc
index bfd8303bc3f29cc8126b87411fe8168bacf42380..44efbc680e1ffcadc35e869f2d6a094410f2909d 100644
--- a/net/http/http_stream_factory_impl.cc
+++ b/net/http/http_stream_factory_impl.cc
@@ -254,6 +254,7 @@ void HttpStreamFactoryImpl::OnNewSpdySessionReady(
       break;
     Request* request = *spdy_session_request_map_[spdy_session_key].begin();
     request->Complete(was_alpn_negotiated, negotiated_protocol, using_spdy);
+    RemoveRequestFromSpdySessionRequestMap(request);
     if (for_websockets_) {
       // TODO(ricea): Restore this code path when WebSocket over SPDY
       // implementation is ready.
@@ -413,4 +414,18 @@ void HttpStreamFactoryImpl::DumpMemoryStats(
                           preconnect_controller_count);
 }
 
+void HttpStreamFactoryImpl::RemoveRequestFromSpdySessionRequestMap(
+    Request* request) {
+  const SpdySessionKey* spdy_session_key = request->spdy_session_key();
+  if (!spdy_session_key)
+    return;
+  if (!base::ContainsKey(spdy_session_request_map_, *spdy_session_key))

[Bence, 2017/03/31 16:21:27]

Please use |iterator it = find(*spdy_session_key); if (iterator == end())
return; request_set = it.second;| or something similar to avoid doing the lookup
twice.

[xunjieli, 2017/03/31 17:45:26]

Done.

+    return;
+  RequestSet& request_set = spdy_session_request_map_[*spdy_session_key];
+  if (base::ContainsKey(request_set, request))

[Bence, 2017/03/31 16:21:27]

Skip the ContainsKey() call in order to avoid doing the lookup twice: it is
valid to call erase() even if the key does not exist, in which case it is a
no-op.  Maybe add a comment if you think it is necessary.

[xunjieli, 2017/03/31 17:45:26]

Done.

+    request_set.erase(request);
+  if (request_set.empty())
+    spdy_session_request_map_.erase(*spdy_session_key);

[Bence, 2017/03/31 16:21:27]

And use the iterator here to avoid the third lookup.

[xunjieli, 2017/03/31 17:45:26]

Done. Good idea!

+}
+
 }  // namespace net