Add trace event for addition/removal of GPU rasterization trigger

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 e77b86804239238cf6e767c0d6527c10a0c6aeab..ef6e74fabe0d763f6e2e38678399b32484552449 100644
--- a/cc/trees/layer_tree_host.h
+++ b/cc/trees/layer_tree_host.h
@@ -186,9 +186,7 @@ class CC_EXPORT LayerTreeHost {
   bool has_gpu_rasterization_trigger() const {
     return has_gpu_rasterization_trigger_;
   }
-  void set_has_gpu_rasterization_trigger(bool has_trigger) {
-    has_gpu_rasterization_trigger_ = has_trigger;
-  }
+  void SetHasGpuRasterizationTrigger(bool has_trigger);
   bool UseGpuRasterization() const;
 
   void SetViewportSize(const gfx::Size& device_viewport_size);