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 20b5e4934149f3fffc1343ca15626e49cf75c6bd..99db507e26dd6bc1a2c8c54beada2d9ef3dcd543 100644
--- a/cc/layers/nine_patch_layer.h
+++ b/cc/layers/nine_patch_layer.h
@@ -41,6 +41,11 @@ class CC_EXPORT NinePatchLayer : public UIResourceLayer {
   void SetFillCenter(bool fill_center);
   void SetNearestNeighbor(bool nearest_neighbor);
 
+  // |rect| is the space completly occluded by another layer in layer space.

[Daniel Erat, 2016/04/15 15:38:45]

nit: s/completly/completely/

[llandwerlin-old, 2016/04/18 15:08:20]

Done.

+  // 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& rect);
+
  private:
   NinePatchLayer();
   ~NinePatchLayer() override;
@@ -54,6 +59,8 @@ class CC_EXPORT NinePatchLayer : public UIResourceLayer {
   // image space.
   gfx::Rect image_aperture_;
 
+  gfx::Rect layer_occlusion_;

[Daniel Erat, 2016/04/15 15:38:45]

nit: add a brief comment describing this member (maybe just "Occluded area in
layer space set by SetLayerOcclusion.")

[llandwerlin-old, 2016/04/18 15:08:20]

Done.

+
   DISALLOW_COPY_AND_ASSIGN(NinePatchLayer);
 };