Send FrameSwapMessageQueue's messages with a separate IPC

content/common/view_messages.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // IPC messages for page rendering.
 // Multiply-included message file, hence no include guard.
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 785 matching lines @@
                     int /* minimum_percent */,
                     int /* maximum_percent */)
 
 IPC_MESSAGE_ROUTED4(
     ViewHostMsg_SwapCompositorFrame,
     uint32_t /* compositor_frame_sink_id */,
     cc::LocalSurfaceId /* local_surface_id */,
     cc::CompositorFrame /* frame */,
     std::vector<IPC::Message> /* messages_to_deliver_with_frame */)
 
+IPC_MESSAGE_ROUTED2(ViewHostMsg_FrameSwapMessages,

[Fady Samuel, 2017/03/31 16:45:14]

I really don't like this name...I don't like "swap" at all, because we don't
really "swap"...it's Submit.

ViewHostMsg_CompositorFrameAlignedMessages?

[Saman Sami, 2017/04/03 19:22:28]

I chose that name because of FrameSwapMessageQueue. "Swap" doesn't make sense if
we take it literally, but we already use it extensively to mean submitting
frames, right?

+                    uint32_t /* frame_id */,
+                    std::vector<IPC::Message> /* messages */)
+
 // Sent if the BeginFrame did not cause a SwapCompositorFrame (e.g. because no
 // updates were required or because it was aborted in the renderer).
 IPC_MESSAGE_ROUTED1(ViewHostMsg_BeginFrameDidNotSwap,
                     cc::BeginFrameAck /* ack */)
 
 // Send back a string to be recorded by UserMetrics.
 IPC_MESSAGE_CONTROL1(ViewHostMsg_UserMetricsRecordAction,
                      std::string /* action */)
 
 // Notifies the browser of an event occurring in the media pipeline.
@@ skipping 68 matching lines @@
                     int /* y */)
 
 #elif defined(OS_MACOSX)
 // Receives content of a web page as plain text.
 IPC_MESSAGE_ROUTED1(ViewMsg_GetRenderedTextCompleted, std::string)
 #endif
 
 // Adding a new message? Stick to the sort order above: first platform
 // independent ViewMsg, then ifdefs for platform specific ViewMsg, then platform
 // independent ViewHostMsg, then ifdefs for platform specific ViewHostMsg.