app_list: Fix shadow bleeds over launcher button and steals mouse events

ui/views/widget/native_widget_delegate.h

Index: ui/views/widget/native_widget_delegate.h
diff --git a/ui/views/widget/native_widget_delegate.h b/ui/views/widget/native_widget_delegate.h
index 41e38e7710ec0343d34c724a1c9459983b9d6384..35bc61cf6b1dc2932f6fd6467bc28439a29db2cd 100644
--- a/ui/views/widget/native_widget_delegate.h
+++ b/ui/views/widget/native_widget_delegate.h
@@ -11,6 +11,7 @@
 
 namespace gfx {
 class Canvas;
+class Path;
 class Point;
 class Size;
 }
@@ -113,6 +114,12 @@ class VIEWS_EXPORT NativeWidgetDelegate {
   // if the widget doesn't have input method.
   virtual InputMethod* GetInputMethodDirect() = 0;
 
+  // Returns true if window has a hit-test mask.
+  virtual bool HasHitTestMask() const = 0;
+
+  // Provides the hit-test mask if HasHitTestMask above returns true.
+  virtual void GetHitTestMask(gfx::Path* mask) const = 0;
+
   //
   virtual Widget* AsWidget() = 0;
   virtual const Widget* AsWidget() const = 0;