cc: Unify the occlusion access by adding an ability to scale transform.

cc/trees/occlusion.h

Index: cc/trees/occlusion.h
diff --git a/cc/trees/occlusion.h b/cc/trees/occlusion.h
index 60493cc2f7d5ff737469cd84adfa8a8daf5a3a4f..a1808c71ea526b8fe0b019ad33aa740c7b3b7024 100644
--- a/cc/trees/occlusion.h
+++ b/cc/trees/occlusion.h
@@ -19,7 +19,9 @@ class CC_EXPORT Occlusion {
   Occlusion(const gfx::Transform& draw_transform,
             const SimpleEnclosedRegion& occlusion_from_outside_target,
             const SimpleEnclosedRegion& occlusion_from_inside_target);
+  Occlusion GetOcclusionWithScaledDrawTransform(SkMScalar x, SkMScalar y);
 
+  bool HasOcclusion() const;
   bool IsOccluded(const gfx::Rect& content_rect) const;
   gfx::Rect GetUnoccludedContentRect(const gfx::Rect& content_rect) const;