cc: Move main thread hierarchy dependencies into PropertyTreeBuilder

cc/trees/layer_tree_host.h

Index: cc/trees/layer_tree_host.h
diff --git a/cc/trees/layer_tree_host.h b/cc/trees/layer_tree_host.h
index 7c18a8ac7e6c28a0a3f5db4f3b98f3962e1e7411..e00b8e7aff9447050e9d19e974bc25435a9e4a54 100644
--- a/cc/trees/layer_tree_host.h
+++ b/cc/trees/layer_tree_host.h
@@ -149,6 +149,8 @@ class CC_EXPORT LayerTreeHost : public MutatorHostClient {
 
   LayerListIterator<Layer> begin();
   LayerListIterator<Layer> end();
+  const LayerListIterator<Layer> begin() const;
+  const LayerListIterator<Layer> end() const;
   LayerListReverseIterator<Layer> rbegin();
   LayerListReverseIterator<Layer> rend();
 
@@ -171,18 +173,10 @@ class CC_EXPORT LayerTreeHost : public MutatorHostClient {
 
   int source_frame_number() const { return source_frame_number_; }
 
-  int meta_information_sequence_number() {
-    return meta_information_sequence_number_;
-  }
-
   bool gpu_rasterization_histogram_recorded() const {
     return gpu_rasterization_histogram_recorded_;
   }
 
-  void IncrementMetaInformationSequenceNumber() {
-    meta_information_sequence_number_++;
-  }
-
   void SetNeedsDisplayOnAllLayers();
 
   void SetOutputIsSecure(bool output_is_secure);
@@ -507,7 +501,6 @@ class CC_EXPORT LayerTreeHost : public MutatorHostClient {
   std::unique_ptr<TaskRunnerProvider> task_runner_provider_;
 
   int source_frame_number_;
-  int meta_information_sequence_number_;
   std::unique_ptr<RenderingStatsInstrumentation>
       rendering_stats_instrumentation_;