cc: Allow the main thread to cancel commits

cc/test/fake_picture_layer.h

Index: cc/test/fake_picture_layer.h
diff --git a/cc/test/fake_picture_layer.h b/cc/test/fake_picture_layer.h
index b5b81de1d7a6b6f0e522013a6dabaf84970180e9..55dbfa7d2eeb508ba0760710efbe7396db5c5988 100644
--- a/cc/test/fake_picture_layer.h
+++ b/cc/test/fake_picture_layer.h
@@ -26,6 +26,10 @@ class FakePictureLayer : public PictureLayer {
   size_t push_properties_count() const { return push_properties_count_; }
   void reset_push_properties_count() { push_properties_count_ = 0; }
 
+  void set_always_update_resources(bool always_update_resources) {
+    always_update_resources_ = always_update_resources;
+  }
+
   virtual bool Update(
       ResourceUpdateQueue* queue,
       const OcclusionTracker* occlusion) OVERRIDE;
@@ -38,6 +42,7 @@ class FakePictureLayer : public PictureLayer {
 
   size_t update_count_;
   size_t push_properties_count_;
+  bool always_update_resources_;
 };
 
 }  // namespace cc