cc: nine patch: add occlusion support

ui/compositor/layer.cc

Index: ui/compositor/layer.cc
diff --git a/ui/compositor/layer.cc b/ui/compositor/layer.cc
index 83409bb748fc9d82976b43678174cd4612f488be..7dcf17724f2ca838e763b2198a5a347d6f13a22a 100644
--- a/ui/compositor/layer.cc
+++ b/ui/compositor/layer.cc
@@ -650,10 +650,16 @@ void Layer::UpdateNinePatchLayerAperture(const gfx::Rect& aperture_in_dip) {
 }
 
 void Layer::UpdateNinePatchLayerBorder(const gfx::Rect& border) {
-  DCHECK(type_ == LAYER_NINE_PATCH && nine_patch_layer_.get());
+  DCHECK_EQ(type_, LAYER_NINE_PATCH);
+  DCHECK(nine_patch_layer_.get());
   nine_patch_layer_->SetBorder(border);
 }
 
+void Layer::UpdateNinePatchOcclusion(const gfx::Rect& occlusion) {
+  DCHECK(type_ == LAYER_NINE_PATCH && nine_patch_layer_.get());
+  nine_patch_layer_->SetLayerOcclusion(occlusion);
+}
+
 void Layer::SetColor(SkColor color) { GetAnimator()->SetColor(color); }
 
 SkColor Layer::GetTargetColor() {
@@ -842,6 +848,7 @@ void Layer::StackRelativeTo(Layer* child, Layer* other, bool above) {
       above ?
       (child_i < other_i ? other_i : other_i + 1) :
       (child_i < other_i ? other_i - 1 : other_i);
+
   children_.erase(children_.begin() + child_i);
   children_.insert(children_.begin() + dest_i, child);