cc: Make BackToBackBeginFrameSource a SyntheticBeginFrameSource.

content/renderer/gpu/compositor_external_begin_frame_source.cc

 // Copyright 2014 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/compositor_external_begin_frame_source.h"
 
 #include "content/common/view_messages.h"
 #include "ipc/ipc_sync_channel.h"
 #include "ipc/ipc_sync_message_filter.h"
 
@@ skipping 14 matching lines @@
 CompositorExternalBeginFrameSource::~CompositorExternalBeginFrameSource() {
   DCHECK(CalledOnValidThread());
   if (begin_frame_source_proxy_.get()) {
     begin_frame_source_proxy_->ClearBeginFrameSource();
     begin_frame_source_filter_->RemoveHandlerOnCompositorThread(
                                     routing_id_,
                                     begin_frame_source_filter_handler_);
   }
 }
 
-void CompositorExternalBeginFrameSource::OnNeedsBeginFramesChanged(
-    bool needs_begin_frames) {
-  DCHECK(CalledOnValidThread());
-  if (!needs_begin_frames)
-    missed_begin_frame_args_ = cc::BeginFrameArgs();
-  Send(new ViewHostMsg_SetNeedsBeginFrames(routing_id_, needs_begin_frames));
-}
-
 void CompositorExternalBeginFrameSource::AddObserver(
     cc::BeginFrameObserver* obs) {
   DCHECK(CalledOnValidThread());
+  DCHECK(obs);
+  DCHECK(observers_.find(obs) == observers_.end());
+
   SetClientReady();
-  BeginFrameSourceBase::AddObserver(obs);
+  bool observers_was_empty = observers_.empty();
+  observers_.insert(obs);
+  obs->OnBeginFrameSourcePausedChanged(paused_);
+  if (observers_was_empty)
+    Send(new ViewHostMsg_SetNeedsBeginFrames(routing_id_, true));
+
   // Send a MISSED begin frame if necessary.
   if (missed_begin_frame_args_.IsValid()) {
     cc::BeginFrameArgs last_args = obs->LastUsedBeginFrameArgs();
     if (!last_args.IsValid() ||
         (missed_begin_frame_args_.frame_time > last_args.frame_time)) {
       obs->OnBeginFrame(missed_begin_frame_args_);
     }
   }
 }
 
+void CompositorExternalBeginFrameSource::RemoveObserver(
+    cc::BeginFrameObserver* obs) {
+  DCHECK(obs);
+  DCHECK(observers_.find(obs) != observers_.end());
+
+  observers_.erase(obs);
+  if (observers_.empty()) {
+    missed_begin_frame_args_ = cc::BeginFrameArgs();
+    Send(new ViewHostMsg_SetNeedsBeginFrames(routing_id_, false));
+  }
+}
+
 void CompositorExternalBeginFrameSource::SetClientReady() {
   DCHECK(CalledOnValidThread());
   if (begin_frame_source_proxy_)
     return;
   begin_frame_source_proxy_ =
       new CompositorExternalBeginFrameSourceProxy(this);
   begin_frame_source_filter_handler_ = base::Bind(
       &CompositorExternalBeginFrameSourceProxy::OnMessageReceived,
       begin_frame_source_proxy_);
   begin_frame_source_filter_->AddHandlerOnCompositorThread(
       routing_id_,
       begin_frame_source_filter_handler_);
 }
 
 void CompositorExternalBeginFrameSource::OnMessageReceived(
     const IPC::Message& message) {
   DCHECK(CalledOnValidThread());
   DCHECK(begin_frame_source_proxy_.get());
   IPC_BEGIN_MESSAGE_MAP(CompositorExternalBeginFrameSource, message)
-    IPC_MESSAGE_HANDLER(ViewMsg_SetBeginFramePaused, SetBeginFrameSourcePaused)
+    IPC_MESSAGE_HANDLER(ViewMsg_SetBeginFramePaused,
+                        OnSetBeginFrameSourcePaused)
     IPC_MESSAGE_HANDLER(ViewMsg_BeginFrame, OnBeginFrame)
   IPC_END_MESSAGE_MAP()
 }
 
+void CompositorExternalBeginFrameSource::OnSetBeginFrameSourcePaused(
+    bool paused) {
+  if (paused_ == paused)
+    return;
+  paused_ = paused;
+  std::unordered_set<cc::BeginFrameObserver*> observers(observers_);
+  for (auto* obs : observers)
+    obs->OnBeginFrameSourcePausedChanged(paused_);
+}
+
 void CompositorExternalBeginFrameSource::OnBeginFrame(
   const cc::BeginFrameArgs& args) {
   DCHECK(CalledOnValidThread());
   missed_begin_frame_args_ = args;
   missed_begin_frame_args_.type = cc::BeginFrameArgs::MISSED;
-  CallOnBeginFrame(args);
+  std::unordered_set<cc::BeginFrameObserver*> observers(observers_);
+  for (auto* obs : observers)
+    obs->OnBeginFrame(args);
 }
 
 bool CompositorExternalBeginFrameSource::Send(IPC::Message* message) {
   return message_sender_->Send(message);
 }
 
 }  // namespace content