Send FrameSwapMessageQueue's messages with a separate IPC

content/renderer/gpu/renderer_compositor_frame_sink.cc

 // 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.
 
 #include "content/renderer/gpu/renderer_compositor_frame_sink.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/location.h"
@@ skipping 31 matching lines @@
       compositor_frame_sink_id_(compositor_frame_sink_id),
       compositor_frame_sink_filter_(
           RenderThreadImpl::current()->compositor_message_filter()),
       message_sender_(RenderThreadImpl::current()->sync_message_filter()),
       frame_swap_message_queue_(swap_frame_message_queue),
       synthetic_begin_frame_source_(std::move(synthetic_begin_frame_source)),
       external_begin_frame_source_(
           synthetic_begin_frame_source_
               ? nullptr
               : base::MakeUnique<cc::ExternalBeginFrameSource>(this)),
-      routing_id_(routing_id) {
+      routing_id_(routing_id),
+      last_used_frame_token_(compositor_frame_sink_id << 28) {

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

I'd rather FrameToken be a struct with two ints like FrameSinkId instead of a
single int with a bunch of bit shifting.. It's easier to read and understand
that way.

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

What should those two ints be called? Frame token is a general-purpose token
that any two parent / child should be able to use. I'm afraid that we might make
it too browser/renderer-specific by splitting it into two ints because that's
renderer's implementation to some extent.

   DCHECK(compositor_frame_sink_filter_);
   DCHECK(frame_swap_message_queue_);
   DCHECK(message_sender_);
   thread_checker_.DetachFromThread();
 }
 
 RendererCompositorFrameSink::RendererCompositorFrameSink(
     int32_t routing_id,
     uint32_t compositor_frame_sink_id,
     std::unique_ptr<cc::SyntheticBeginFrameSource> synthetic_begin_frame_source,
     scoped_refptr<cc::VulkanContextProvider> vulkan_context_provider,
     scoped_refptr<FrameSwapMessageQueue> swap_frame_message_queue)
     : CompositorFrameSink(std::move(vulkan_context_provider)),
       compositor_frame_sink_id_(compositor_frame_sink_id),
       compositor_frame_sink_filter_(
           RenderThreadImpl::current()->compositor_message_filter()),
       message_sender_(RenderThreadImpl::current()->sync_message_filter()),
       frame_swap_message_queue_(swap_frame_message_queue),
       synthetic_begin_frame_source_(std::move(synthetic_begin_frame_source)),
       external_begin_frame_source_(
           synthetic_begin_frame_source_
               ? nullptr
               : base::MakeUnique<cc::ExternalBeginFrameSource>(this)),
-      routing_id_(routing_id) {
+      routing_id_(routing_id),
+      last_used_frame_token_(compositor_frame_sink_id << 28) {
   DCHECK(compositor_frame_sink_filter_);
   DCHECK(frame_swap_message_queue_);
   DCHECK(message_sender_);
   thread_checker_.DetachFromThread();
 }
 
 RendererCompositorFrameSink::~RendererCompositorFrameSink() {
   // TODO(crbug.com/702764): If not detached then IPC messages would crash
   // after this class is destroyed.
   CHECK(!bound_);
@@ skipping 36 matching lines @@
 }
 
 void RendererCompositorFrameSink::SubmitCompositorFrame(
     cc::CompositorFrame frame) {
   // We should only submit CompositorFrames with valid BeginFrameAcks.
   DCHECK_LE(cc::BeginFrameArgs::kStartingFrameNumber,
             frame.metadata.begin_frame_ack.sequence_number);
   if (ShouldAllocateNewLocalSurfaceId(frame))
     local_surface_id_ = id_allocator_.GenerateId();
   UpdateFrameData(frame);
+
   {
     std::unique_ptr<FrameSwapMessageQueue::SendMessageScope>
         send_message_scope =
             frame_swap_message_queue_->AcquireSendMessageScope();
     std::vector<std::unique_ptr<IPC::Message>> messages;
-    std::vector<IPC::Message> messages_to_deliver_with_frame;
     frame_swap_message_queue_->DrainMessages(&messages);
-    FrameSwapMessageQueue::TransferMessages(&messages,
-                                            &messages_to_deliver_with_frame);
-    Send(new ViewHostMsg_SwapCompositorFrame(
-        routing_id_, compositor_frame_sink_id_, local_surface_id_, frame,
-        messages_to_deliver_with_frame));
+    std::vector<IPC::Message> messages_to_send;
+    std::vector<IPC::Message> dummy;
+    FrameSwapMessageQueue::TransferMessages(&messages, &messages_to_send);
+    uint32_t frame_token = 0;
+    if (!messages_to_send.empty())
+      frame_token = ++last_used_frame_token_;
+    frame.metadata.frame_token = frame_token;
+    Send(new ViewHostMsg_SwapCompositorFrame(routing_id_,
+                                             compositor_frame_sink_id_,
+                                             local_surface_id_, frame, dummy));
+    if (frame_token) {
+      Send(new ViewHostMsg_FrameSwapMessages(routing_id_, frame_token,
+                                             messages_to_send));
+    }
     // ~send_message_scope.
   }
 }
 
 void RendererCompositorFrameSink::OnMessageReceived(
     const IPC::Message& message) {
   DCHECK(thread_checker_.CalledOnValidThread());
   IPC_BEGIN_MESSAGE_MAP(RendererCompositorFrameSink, message)
     IPC_MESSAGE_HANDLER(ViewMsg_ReclaimCompositorResources,
                         OnReclaimCompositorResources)
@@ skipping 83 matching lines @@
 
 void RendererCompositorFrameSink::OnDidFinishFrame(
     const cc::BeginFrameAck& ack) {
   DCHECK_LE(cc::BeginFrameArgs::kStartingFrameNumber, ack.sequence_number);
   // If there was damage, ViewHostMsg_SwapCompositorFrame includes the ack.
   if (!ack.has_damage)
     Send(new ViewHostMsg_BeginFrameDidNotSwap(routing_id_, ack));
 }
 
 }  // namespace content