Revert of cc: nine patch: add occlusion support

cc/layers/nine_patch_layer.h

Index: cc/layers/nine_patch_layer.h
diff --git a/cc/layers/nine_patch_layer.h b/cc/layers/nine_patch_layer.h
index accdc70437b005b3936a9c87b6bed370da782282..1c2d7259e3e5b33e0f1cac97d13bc1839723b47e 100644
--- a/cc/layers/nine_patch_layer.h
+++ b/cc/layers/nine_patch_layer.h
@@ -42,11 +42,6 @@
   void SetFillCenter(bool fill_center);
   void SetNearestNeighbor(bool nearest_neighbor);
 
-  // |rect| is the space completely occluded by another layer in layer
-  // space. This can be used for example to occlude the entire window's
-  // content when drawing the shadow with a 9 patches layer.
-  void SetLayerOcclusion(const gfx::Rect& occlusion);
-
  private:
   NinePatchLayer();
   ~NinePatchLayer() override;
@@ -60,10 +55,6 @@
   // image space.
   gfx::Rect image_aperture_;
 
-  // The occluded region in layer space set by SetLayerOcclusion. It is
-  // usually larger than |image_aperture_|.
-  gfx::Rect layer_occlusion_;
-
   DISALLOW_COPY_AND_ASSIGN(NinePatchLayer);
 };