Turn off computation of the interest rect in cc in synchronized paint mode.

cc/test/fake_content_layer_client.cc

Index: cc/test/fake_content_layer_client.cc
diff --git a/cc/test/fake_content_layer_client.cc b/cc/test/fake_content_layer_client.cc
index 0238498d4ec46f4c08036887005b6578259719f7..553bf658a6754810ca8e10f47de7aab864d59ca8 100644
--- a/cc/test/fake_content_layer_client.cc
+++ b/cc/test/fake_content_layer_client.cc
@@ -35,6 +35,11 @@ FakeContentLayerClient::FakeContentLayerClient()
 FakeContentLayerClient::~FakeContentLayerClient() {
 }
 
+gfx::Rect FakeContentLayerClient::PaintableRegion() {
+  CHECK(bounds_set_);
+  return gfx::Rect(bounds_);
+}
+
 scoped_refptr<DisplayItemList>
 FakeContentLayerClient::PaintContentsToDisplayList(
     const gfx::Rect& clip,