Revert "Re-land deferred compositing updates with fixed assumptions"

Source/core/inspector/InspectorLayerTreeAgent.cpp

 /*
  * Copyright (C) 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 90 matching lines @@
         gatherGraphicsLayers(replica, layerIdToNodeIdMap, layers);
     for (size_t i = 0, size = root->children().size(); i < size; ++i)
         gatherGraphicsLayers(root->children()[i], layerIdToNodeIdMap, layers);
 }
 
 InspectorLayerTreeAgent::InspectorLayerTreeAgent(InstrumentingAgents* instrumentingAgents, InspectorCompositeState* state, InspectorDOMAgent* domAgent, Page* page)
     : InspectorBaseAgent<InspectorLayerTreeAgent>("LayerTree", instrumentingAgents, state)
     , m_frontend(0)
     , m_page(page)
     , m_domAgent(domAgent)
+    , m_notificationTimer(this, &InspectorLayerTreeAgent::notificationTimerFired)
+    , m_notifyAfterNextLayersUpdate(false)
 {
 }
 
 InspectorLayerTreeAgent::~InspectorLayerTreeAgent()
 {
 }
 
 void InspectorLayerTreeAgent::setFrontend(InspectorFrontend* frontend)
 {
     m_frontend = frontend->layertree();
@@ skipping 14 matching lines @@
 
 void InspectorLayerTreeAgent::enable(ErrorString*)
 {
     m_instrumentingAgents->setInspectorLayerTreeAgent(this);
     layerTreeDidChange();
 }
 
 void InspectorLayerTreeAgent::disable(ErrorString*)
 {
     m_instrumentingAgents->setInspectorLayerTreeAgent(0);
+    m_notificationTimer.stop();
 }
 
 void InspectorLayerTreeAgent::layerTreeDidChange()
 {
+    if (m_notificationTimer.isActive())
+        return;
+    if (m_notifyAfterNextLayersUpdate) {
+        m_notifyAfterNextLayersUpdate = false;
+        m_frontend->layerTreeDidChange(buildLayerTree());
+        return;
+    }
+    const double layerTreeUpdateDelayInSeconds = 0.1;
+    m_notificationTimer.startOneShot(layerTreeUpdateDelayInSeconds);
+}
+
+void InspectorLayerTreeAgent::notificationTimerFired(Timer<InspectorLayerTreeAgent>*)
+{
+    RenderLayerCompositor* compositor = renderLayerCompositor();
+    if (compositor && compositor->compositingLayersNeedRebuild()) {
+        // Bad time for building layer tree -- let's do it as soon as it gets rebuild.
+        m_notifyAfterNextLayersUpdate = true;
+        return;
+    }
     m_frontend->layerTreeDidChange(buildLayerTree());
 }
 
 void InspectorLayerTreeAgent::didPaint(RenderObject* renderer, GraphicsContext*, const LayoutRect& rect)
 {
     RenderLayer* renderLayer = toRenderLayerModelObject(renderer)->layer();
     CompositedLayerMapping* compositedLayerMapping = renderLayer->compositedLayerMapping();
     // Should only happen for FrameView paints when compositing is off. Consider different instrumentation method for that.
     if (!compositedLayerMapping)
         return;
     GraphicsLayer* graphicsLayer = compositedLayerMapping->mainGraphicsLayer();
     RefPtr<TypeBuilder::DOM::Rect> domRect = TypeBuilder::DOM::Rect::create()
         .setX(rect.x())
         .setY(rect.y())
         .setWidth(rect.width())
         .setHeight(rect.height());
     m_frontend->layerPainted(idForLayer(graphicsLayer), domRect.release());
 }
 
 PassRefPtr<TypeBuilder::Array<TypeBuilder::LayerTree::Layer> > InspectorLayerTreeAgent::buildLayerTree()
 {
     RenderLayerCompositor* compositor = renderLayerCompositor();
     if (!compositor || !compositor->inCompositingMode())
         return 0;
+    // Caller is responsible for only calling this when layer tree is up to date (preferrably just in the end of RenderLayerCompositor::updateCompositingLayers()
+    ASSERT(!compositor->compositingLayersNeedRebuild());
     LayerIdToNodeIdMap layerIdToNodeIdMap;
     RefPtr<TypeBuilder::Array<TypeBuilder::LayerTree::Layer> > layers = TypeBuilder::Array<TypeBuilder::LayerTree::Layer>::create();
     buildLayerIdToNodeIdMap(compositor->rootRenderLayer(), layerIdToNodeIdMap);
     gatherGraphicsLayers(compositor->rootGraphicsLayer(), layerIdToNodeIdMap, layers);
     return layers.release();
 }
 
 void InspectorLayerTreeAgent::buildLayerIdToNodeIdMap(RenderLayer* root, LayerIdToNodeIdMap& layerIdToNodeIdMap)
 {
     if (root->compositedLayerMapping()) {
@@ skipping 115 matching lines @@
             continue;
         reasonStrings->addItem(compositingReasonNames[i].protocolName);
 #ifndef _NDEBUG
         reasonsBitmask &= ~compositingReasonNames[i].mask;
 #endif
     }
     ASSERT(!reasonsBitmask);
 }
 
 } // namespace WebCore