Avoid sending double responding close control frames in WebSockets

This avoids sending a second ack close frame when we get a flow
control request from the renderer while waiting for the connection to
be closed.

BUG=

Review-Url: https://codereview.chromium.org/2845033002
Cr-Commit-Position: refs/heads/master@{#467964}

net/websockets/websocket_channel.cc

@@ -477,7 +477,8 @@ ChannelState WebSocketChannel::SendFlowControl(int64_t quota) {
 
     pending_received_frames_.pop();
   }
-  if (pending_received_frames_.empty() && has_received_close_frame_) {
+  if (!InClosingState() && pending_received_frames_.empty() &&
+      has_received_close_frame_) {
     // We've been waiting for the client to consume the frames before
     // responding to the closing handshake initiated by the server.
     return RespondToClosingHandshake();

net/websockets/websocket_channel_test.cc

@@ -2542,6 +2542,39 @@ TEST_F(WebSocketChannelFlowControlTest, CloseFrameShouldNotOvertakeDataFrames) {
   checkpoint.Call(4);
 }
 
+// SendFlowControl calls should not trigger multiple close respond frames.
+TEST_F(WebSocketChannelFlowControlTest, DoNotSendMultipleCloseRespondFrames) {
+  std::unique_ptr<ReadableFakeWebSocketStream> stream(
+      new ReadableFakeWebSocketStream);
+  static constexpr InitFrame frames[] = {
+      {FINAL_FRAME, WebSocketFrameHeader::kOpCodeText, NOT_MASKED,
+       "FIRST SECOND"},
+      {FINAL_FRAME, WebSocketFrameHeader::kOpCodeClose, NOT_MASKED,
+       CLOSE_DATA(NORMAL_CLOSURE, "GOOD BYE")},
+  };
+  stream->PrepareReadFrames(ReadableFakeWebSocketStream::SYNC, OK, frames);
+  set_stream(std::move(stream));
+  Checkpoint checkpoint;
+  InSequence s;
+  EXPECT_CALL(*event_interface_, OnAddChannelResponse(_, _));
+  EXPECT_CALL(*event_interface_, OnFlowControl(_));
+  EXPECT_CALL(*event_interface_,
+              OnDataFrameVector(false, WebSocketFrameHeader::kOpCodeText,
+                                AsVector("FIRST ")));
+  EXPECT_CALL(checkpoint, Call(1));
+  EXPECT_CALL(*event_interface_,
+              OnDataFrameVector(true, WebSocketFrameHeader::kOpCodeContinuation,
+                                AsVector("SECOND")));
+  EXPECT_CALL(*event_interface_, OnClosingHandshake());
+  EXPECT_CALL(checkpoint, Call(2));
+
+  CreateChannelAndConnectWithQuota(6);
+  checkpoint.Call(1);
+  ASSERT_EQ(CHANNEL_ALIVE, channel_->SendFlowControl(6));
+  checkpoint.Call(2);
+  ASSERT_EQ(CHANNEL_ALIVE, channel_->SendFlowControl(6));
+}
+
 // RFC6455 5.1 "a client MUST mask all frames that it sends to the server".
 // WebSocketChannel actually only sets the mask bit in the header, it doesn't
 // perform masking itself (not all transports actually use masking).