Change ScrollbarLayer to use UI resource

cc/test/fake_scrollbar_layer.h

Index: cc/test/fake_scrollbar_layer.h
diff --git a/cc/test/fake_scrollbar_layer.h b/cc/test/fake_scrollbar_layer.h
index 43be832f34d105b56e815cb6fd9285f6b45e6283..21d0399d4d91ac98578b6f2c4976eb56f62bb266 100644
--- a/cc/test/fake_scrollbar_layer.h
+++ b/cc/test/fake_scrollbar_layer.h
@@ -23,12 +23,6 @@ class FakeScrollbarLayer : public ScrollbarLayer {
 
   int update_count() const { return update_count_; }
   void reset_update_count() { update_count_ = 0; }
-  size_t last_update_full_upload_size() const {
-    return last_update_full_upload_size_;
-  }
-  size_t last_update_partial_upload_size() const {
-    return last_update_partial_upload_size_;
-  }
 
   virtual bool Update(ResourceUpdateQueue* queue,
                       const OcclusionTracker* occlusion) OVERRIDE;
@@ -40,6 +34,14 @@ class FakeScrollbarLayer : public ScrollbarLayer {
   size_t push_properties_count() const { return push_properties_count_; }
   void reset_push_properties_count() { push_properties_count_ = 0; }
 
+  // For unit tests
+  UIResourceId track_resource_id() {
+    return ScrollbarLayer::track_resource_id();
+  }
+  UIResourceId thumb_resource_id() {
+    return ScrollbarLayer::thumb_resource_id();
+  }
+
  private:
   FakeScrollbarLayer(bool paint_during_update,
                      bool has_thumb,
@@ -48,8 +50,6 @@ class FakeScrollbarLayer : public ScrollbarLayer {
 
   int update_count_;
   size_t push_properties_count_;
-  size_t last_update_full_upload_size_;
-  size_t last_update_partial_upload_size_;
 };
 
 }  // namespace cc