cc: Return resources to child compositor via a Callback.

cc/trees/single_thread_proxy.cc

 // Copyright 2011 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 "cc/trees/single_thread_proxy.h"
 
 #include "base/auto_reset.h"
 #include "base/debug/trace_event.h"
 #include "cc/output/context_provider.h"
 #include "cc/output/output_surface.h"
@@ skipping 107 matching lines @@
   if (created_offscreen_context_provider_) {
     offscreen_context_provider =
         layer_tree_host_->client()->OffscreenContextProviderForMainThread();
     if (!offscreen_context_provider.get()) {
       OnOutputSurfaceInitializeAttempted(false);
       return;
     }
   }
 
   {
-    DebugScopedSetMainThreadBlocked mainThreadBlocked(this);
+    DebugScopedSetMainThreadBlocked main_thread_blocked(this);
     DebugScopedSetImplThread impl(this);
     layer_tree_host_->DeleteContentsTexturesOnImplThread(
         layer_tree_host_impl_->resource_provider());
   }
 
   bool initialized;
   {
     DebugScopedSetImplThread impl(this);
 
     DCHECK(output_surface);
@@ skipping 36 matching lines @@
 
 void SingleThreadProxy::SetNeedsUpdateLayers() {
   DCHECK(Proxy::IsMainThread());
   layer_tree_host_->ScheduleComposite();
 }
 
 void SingleThreadProxy::DoCommit(scoped_ptr<ResourceUpdateQueue> queue) {
   DCHECK(Proxy::IsMainThread());
   // Commit immediately.
   {
-    DebugScopedSetMainThreadBlocked mainThreadBlocked(this);
+    DebugScopedSetMainThreadBlocked main_thread_blocked(this);
     DebugScopedSetImplThread impl(this);
 
     // This CapturePostTasks should be destroyed before CommitComplete() is
     // called since that goes out to the embedder, and we want the embedder
     // to receive its callbacks before that.
     BlockingTaskRunner::CapturePostTasks blocked;
 
     RenderingStatsInstrumentation* stats_instrumentation =
         layer_tree_host_->rendering_stats_instrumentation();
     base::TimeTicks start_time = stats_instrumentation->StartRecording();
@@ skipping 60 matching lines @@
 bool SingleThreadProxy::CommitRequested() const { return false; }
 
 size_t SingleThreadProxy::MaxPartialTextureUpdates() const {
   return std::numeric_limits<size_t>::max();
 }
 
 void SingleThreadProxy::Stop() {
   TRACE_EVENT0("cc", "SingleThreadProxy::stop");
   DCHECK(Proxy::IsMainThread());
   {
-    DebugScopedSetMainThreadBlocked mainThreadBlocked(this);
+    DebugScopedSetMainThreadBlocked main_thread_blocked(this);
     DebugScopedSetImplThread impl(this);
 
     layer_tree_host_->DeleteContentsTexturesOnImplThread(
         layer_tree_host_impl_->resource_provider());
     layer_tree_host_impl_.reset();
   }
   layer_tree_host_ = NULL;
 }
 
 void SingleThreadProxy::OnCanDrawStateChanged(bool can_draw) {
@@ skipping 81 matching lines @@
 // Called by the legacy scheduling path (e.g. where render_widget does the
 // scheduling)
 void SingleThreadProxy::CompositeImmediately(base::TimeTicks frame_begin_time) {
   gfx::Rect device_viewport_damage_rect;
 
   LayerTreeHostImpl::FrameData frame;
   if (CommitAndComposite(frame_begin_time,
                          device_viewport_damage_rect,
                          false,  // for_readback
                          &frame)) {
-    layer_tree_host_impl_->SwapBuffers(frame);
+    {
+      DebugScopedSetMainThreadBlocked main_thread_blocked(this);
+      DebugScopedSetImplThread impl(this);
+
+      // This CapturePostTasks should be destroyed before
+      // DidCommitAndDrawFrame() is called since that goes out to the embedder,
+      // and we want the embedder to receive its callbacks before that.
+      // NOTE: This maintains consistent ordering with the ThreadProxy since
+      // the DidCommitAndDrawFrame() must be post-tasked from the impl thread
+      // there as the main thread is not blocked, so any posted tasks inside
+      // the swap buffers will execute first.
+      BlockingTaskRunner::CapturePostTasks blocked;
+
+      layer_tree_host_impl_->SwapBuffers(frame);
+    }
     DidSwapFrame();
   }
 }
 
 scoped_ptr<base::Value> SingleThreadProxy::AsValue() const {
   scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue());
   {
     // The following line casts away const modifiers because it is just
     // setting debug state. We still want the AsValue() function and its
     // call chain to be const throughout.
@@ skipping 127 matching lines @@
 void SingleThreadProxy::DidSwapFrame() {
   if (next_frame_is_newly_committed_frame_) {
     next_frame_is_newly_committed_frame_ = false;
     layer_tree_host_->DidCommitAndDrawFrame();
   }
 }
 
 bool SingleThreadProxy::CommitPendingForTesting() { return false; }
 
 }  // namespace cc