cc: Add receiver for CompositorFrameAck in LayerTreeHostImpl and forward it to the renderer.

cc/layer_tree_host_impl.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/layer_tree_host_impl.h"
 
 #include <algorithm>
 
 #include "base/basictypes.h"
 #include "base/debug/trace_event.h"
@@ skipping 798 matching lines @@
     m_client->setNeedsCommitOnImplThread();
 }
 
 void LayerTreeHostImpl::onVSyncParametersChanged(double monotonicTimebase, double intervalInSeconds)
 {
     base::TimeTicks timebase = base::TimeTicks::FromInternalValue(monotonicTimebase * base::Time::kMicrosecondsPerSecond);
     base::TimeDelta interval = base::TimeDelta::FromMicroseconds(intervalInSeconds * base::Time::kMicrosecondsPerSecond);
     m_client->onVSyncParametersChanged(timebase, interval);
 }
 
+void LayerTreeHostImpl::onSendFrameToParentCompositorAck(const WebKit::WebCompositorFrameAck& webAck)
+{
+    if (!m_renderer)
+        return;
+
+    // TODO(piman): We may need to do some validation on this ack before processing it.
+    // TODO(danakj): This cast goes away when we move WebCompositorOutputSurface to cc::OutputSurface.
+    const CompositorFrameAck& ack = reinterpret_cast<const CompositorFrameAck&>(webAck);

[piman, 2012/12/06 18:07:05]

In the mean time, can we just make CompositorFrameAck derive from the (empty)
WebCompositorFrameAck and make this a static_cast ?

+    m_renderer->receiveCompositorFrameAck(ack);
+}
+
 void LayerTreeHostImpl::drawLayers(FrameData& frame)
 {
     TRACE_EVENT0("cc", "LayerTreeHostImpl::drawLayers");
     DCHECK(canDraw());
     DCHECK(!frame.renderPasses.empty());
 
     // FIXME: use the frame begin time from the overall compositor scheduler.
     // This value is currently inaccessible because it is up in Chromium's
     // RenderWidget.
     m_fpsCounter->markBeginningOfFrame(base::TimeTicks::Now());
@@ skipping 803 matching lines @@
     ScrollbarAnimationController* scrollbarController = layer->scrollbarAnimationController();
     double monotonicTime = (time - base::TimeTicks()).InSecondsF();
     if (scrollbarController && scrollbarController->animate(monotonicTime))
         m_client->setNeedsRedrawOnImplThread();
 
     for (size_t i = 0; i < layer->children().size(); ++i)
         animateScrollbarsRecursive(layer->children()[i], time);
 }
 
 }  // namespace cc