cc: Remove map lookup from RenderSurfaceImpl::EffectTreeIndex

cc/trees/layer_tree_host_in_process.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/trees/layer_tree_host_in_process.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 582 matching lines @@
   if (numLayers < 30)
     return 1;
   if (numLayers < 70)
     return 2;
   if (numLayers < 150)
     return 3;
   return 4;
 }
 
 bool LayerTreeHostInProcess::UpdateLayers() {
-  if (!layer_tree_->root_layer())
+  if (!layer_tree_->root_layer()) {
+    layer_tree_->property_trees()->clear();
     return false;
+  }
   DCHECK(!layer_tree_->root_layer()->parent());
   base::ElapsedTimer timer;
 
   bool result = DoUpdateLayers(layer_tree_->root_layer());
   micro_benchmark_controller_.DidUpdateLayers();
 
   if (const char* client_name = GetClientNameForMetrics()) {
     std::string histogram_name = base::StringPrintf(
         "Compositing.%s.LayersUpdateTime.%d", client_name,
         GetLayersUpdateTimeHistogramBucket(layer_tree_->NumLayers()));
@@ skipping 235 matching lines @@
   return compositor_mode_ == CompositorMode::SINGLE_THREADED;
 }
 
 bool LayerTreeHostInProcess::IsThreaded() const {
   DCHECK(compositor_mode_ != CompositorMode::THREADED ||
          task_runner_provider_->HasImplThread());
   return compositor_mode_ == CompositorMode::THREADED;
 }
 
 }  // namespace cc