WillActivateTreeOnThread  107 cc/test/layer_tree_test.cc       test_hooks_->WillActivateTreeOnThread(this);
WillActivateTreeOnThread  162 cc/test/layer_tree_test.cc     test_hooks_->WillActivateTreeOnThread(this);
WillActivateTreeOnThread   45 cc/test/layer_tree_test.h   virtual void WillActivateTreeOnThread(LayerTreeHostImpl* host_impl) {}