Use message passing for BeginFrameAndCommitState and clean up forced commit logic

cc/layer_tree_host.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.h"
 
 #include "base/debug/trace_event.h"
 #include "base/message_loop.h"
 #include "cc/font_atlas.h"
 #include "cc/graphics_context.h"
@@ skipping 482 matching lines @@
     if (m_contextLost) {
         if (recreateContext() != RecreateSucceeded)
             return false;
     }
     return true;
 }
 
 void LayerTreeHost::updateLayers(ResourceUpdateQueue& queue, size_t memoryAllocationLimitBytes)
 {
     DCHECK(m_rendererInitialized);
-    DCHECK(memoryAllocationLimitBytes);
 
     if (!rootLayer())
         return;
 
     if (layoutViewportSize().IsEmpty())
         return;
 
-    m_contentsTextureManager->setMaxMemoryLimitBytes(memoryAllocationLimitBytes);
+    if (memoryAllocationLimitBytes)
+        m_contentsTextureManager->setMaxMemoryLimitBytes(memoryAllocationLimitBytes);
 
     updateLayers(rootLayer(), queue);
 }
 
 static Layer* findFirstScrollableLayer(Layer* layer)
 {
     if (!layer)
         return 0;
 
     if (layer->scrollable())
@@ skipping 314 matching lines @@
             else
                 layer->notifyAnimationFinished(wallClockTime.ToDoubleT());
         }
     }
 
     for (size_t childIndex = 0; childIndex < layer->children().size(); ++childIndex)
         setAnimationEventsRecursive(events, layer->children()[childIndex].get(), wallClockTime);
 }
 
 }  // namespace cc