Re-reland Propagate OnNativeWidgetMove to delegate/observers, etc.

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 4fac0b0d2db40c4e8e75236b92ff6166e9457149..41e38e7710ec0343d34c724a1c9459983b9d6384 100644
--- a/ui/views/widget/native_widget_delegate.h
+++ b/ui/views/widget/native_widget_delegate.h
@@ -72,6 +72,9 @@ class VIEWS_EXPORT NativeWidgetDelegate {
   // Returns the largest size the window can be resized to by the user.
   virtual gfx::Size GetMaximumSize() = 0;
 
+  // Called when the NativeWidget changed position.
+  virtual void OnNativeWidgetMove() = 0;
+
   // Called when the NativeWidget changed size to |new_size|.
   virtual void OnNativeWidgetSizeChanged(const gfx::Size& new_size) = 0;