Canvas2DLayerManager shouldn't use a task observer

sky/engine/platform/graphics/Canvas2DLayerManager.cpp

 /*
 Copyright (C) 2012 Google Inc. All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions
 are met:
 1.  Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.
 2.  Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in the
@@ skipping 25 matching lines @@
 };
 
 } // unnamed namespace
 
 namespace blink {
 
 Canvas2DLayerManager::Canvas2DLayerManager()
     : m_bytesAllocated(0)
     , m_maxBytesAllocated(DefaultMaxBytesAllocated)
     , m_targetBytesAllocated(DefaultTargetBytesAllocated)
-    , m_taskObserverActive(false)
+    , m_limitPendingFramesTimer(this, &Canvas2DLayerManager::limitPendingFramesTimerFired)
 {
 }
 
 Canvas2DLayerManager::~Canvas2DLayerManager()
 {
     ASSERT(!m_bytesAllocated);
     ASSERT(!m_layerList.head());
-    ASSERT(!m_taskObserverActive);
 }
 
 void Canvas2DLayerManager::init(size_t maxBytesAllocated, size_t targetBytesAllocated)
 {
     ASSERT(maxBytesAllocated >= targetBytesAllocated);
     m_maxBytesAllocated = maxBytesAllocated;
     m_targetBytesAllocated = targetBytesAllocated;
-    if (m_taskObserverActive) {
-        Platform::current()->currentThread()->removeTaskObserver(this);
-        m_taskObserverActive = false;
-    }
+    if (m_limitPendingFramesTimer.isActive())
+        m_limitPendingFramesTimer.stop();
 }
 
 Canvas2DLayerManager& Canvas2DLayerManager::get()
 {
     DEFINE_STATIC_LOCAL(Canvas2DLayerManager, manager, ());
     return manager;
 }
 
-void Canvas2DLayerManager::willProcessTask()
+void Canvas2DLayerManager::limitPendingFramesTimerFired(Timer<Canvas2DLayerManager>*)
 {
-}
-
-void Canvas2DLayerManager::didProcessTask()
-{
-    // Called after the script action for the current frame has been processed.
-    ASSERT(m_taskObserverActive);
-    Platform::current()->currentThread()->removeTaskObserver(this);
-    m_taskObserverActive = false;
     Canvas2DLayerBridge* layer = m_layerList.head();
     while (layer) {
         Canvas2DLayerBridge* currentLayer = layer;
         // must increment iterator before calling limitPendingFrames, which
         // may result in the layer being removed from the list.
         layer = layer->next();
         currentLayer->limitPendingFrames();
     }
 }
 
 void Canvas2DLayerManager::layerDidDraw(Canvas2DLayerBridge* layer)
 {
     if (isInList(layer)) {
         if (layer != m_layerList.head()) {
             m_layerList.remove(layer);
             m_layerList.push(layer); // Set as MRU
         }
     }
 
-    if (!m_taskObserverActive) {
-        m_taskObserverActive = true;
-        // Schedule a call to didProcessTask() after completion of the current script task.
-        Platform::current()->currentThread()->addTaskObserver(this);
-    }
+    if (!m_limitPendingFramesTimer.isActive())
+        m_limitPendingFramesTimer.startOneShot(0, FROM_HERE);
 }
 
 void Canvas2DLayerManager::layerTransientResourceAllocationChanged(Canvas2DLayerBridge* layer, intptr_t deltaBytes)
 {
     ASSERT((intptr_t)m_bytesAllocated + deltaBytes >= 0);
     m_bytesAllocated = (intptr_t)m_bytesAllocated + deltaBytes;
     if (!isInList(layer) && layer->hasTransientResources()) {
         m_layerList.push(layer);
     } else if (isInList(layer) && !layer->hasTransientResources()) {
         m_layerList.remove(layer);
@@ skipping 29 matching lines @@
     }
 }
 
 bool Canvas2DLayerManager::isInList(Canvas2DLayerBridge* layer) const
 {
     return layer->prev() || m_layerList.head() == layer;
 }
 
 } // namespace blink