[cc] Route LayerImpl::layerTreeHostImpl() calls through LayerTreeImpl

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 540 matching lines @@
         if (it.representsContributingRenderSurface()) {
             RenderPass::Id contributingRenderPassId = it->renderSurface()->renderPassId();
             RenderPass* contributingRenderPass = frame.renderPassesById.get(contributingRenderPassId);
             appendQuadsForRenderSurfaceLayer(targetRenderPass, *it, contributingRenderPass, occlusionTracker, appendQuadsData);
         } else if (it.representsItself() && !it->visibleContentRect().IsEmpty()) {
             bool hasOcclusionFromOutsideTargetSurface;
             bool implDrawTransformIsUnknown = false;
             if (occlusionTracker.occluded(it->renderTarget(), it->visibleContentRect(), it->drawTransform(), implDrawTransformIsUnknown, it->drawableContentRect(), &hasOcclusionFromOutsideTargetSurface))
                 appendQuadsData.hadOcclusionFromOutsideTargetSurface |= hasOcclusionFromOutsideTargetSurface;
             else {
-                DCHECK_EQ(this, it->layerTreeHostImpl());
+                DCHECK_EQ(this->activeTree(), it->layerTreeImpl());
                 it->willDraw(m_resourceProvider.get());
                 frame.willDrawLayers.push_back(*it);
 
                 if (it->hasContributingDelegatedRenderPasses()) {
                     RenderPass::Id contributingRenderPassId = it->firstContributingRenderPassId();
                     while (frame.renderPassesById.contains(contributingRenderPassId)) {
                         RenderPass* renderPass = frame.renderPassesById.get(contributingRenderPassId);
   
                         AppendQuadsData appendQuadsData(renderPass->id);
                         appendQuadsForLayer(renderPass, *it, occlusionTracker, appendQuadsData);
@@ skipping 1148 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