Send FrameSwapMessageQueue's messages with a separate IPC

content/renderer/gpu/frame_swap_message_queue.h

Index: content/renderer/gpu/frame_swap_message_queue.h
diff --git a/content/renderer/gpu/frame_swap_message_queue.h b/content/renderer/gpu/frame_swap_message_queue.h
index 88a3731bb4b5c286c4d7296c933c1a106ccd7380..3f3a0b436cfc28b793ee86abc49b4e1fd086ba43 100644
--- a/content/renderer/gpu/frame_swap_message_queue.h
+++ b/content/renderer/gpu/frame_swap_message_queue.h
@@ -25,8 +25,10 @@ namespace content {
 
 class FrameSwapMessageSubQueue;
 
-// Queue used to keep track of which IPC::Messages should be sent along with a
-// particular compositor frame swap.
+// Queue used to keep track of which IPC::Messages should be sent after a
+// particular compositor frame swap. The messages are guaranteed to be processed
+// after the frame is processed, but there is no guarantee that nothing else
+// happens between processing the frame and processing the messages.
 class CONTENT_EXPORT FrameSwapMessageQueue
     : public base::RefCountedThreadSafe<FrameSwapMessageQueue> {
  public: