Draggable region support for frameless app window on CrOS.

ui/views/widget/widget_delegate.h

Index: ui/views/widget/widget_delegate.h
diff --git a/ui/views/widget/widget_delegate.h b/ui/views/widget/widget_delegate.h
index 33f3ccd5de25acf6582d222581cbda7f50b9e782..0155ed1cefa8fd6fc7d5a4984c6f68535d9ff138 100644
--- a/ui/views/widget/widget_delegate.h
+++ b/ui/views/widget/widget_delegate.h
@@ -147,6 +147,12 @@ class VIEWS_EXPORT WidgetDelegate {
   // Provides the hit-test mask if HasHitTestMask above returns true.
   virtual void GetHitTestMask(gfx::Path* mask) const;
 
+  // Returns true if event handling should descend into |child|.
+  // |location| is in terms of the Window.
+  virtual bool ShouldDescendIntoChildForEventHandling(
+      gfx::NativeView child,
+      const gfx::Point& location);
+
  protected:
   virtual ~WidgetDelegate() {}