Remove legacy draggable region code and refactor to share common draggable region code

chrome/browser/ui/extensions/native_shell_window.h

Index: chrome/browser/ui/extensions/native_shell_window.h
diff --git a/chrome/browser/ui/extensions/native_shell_window.h b/chrome/browser/ui/extensions/native_shell_window.h
index 96db04ddd855c657c68c9cf8788944979258f137..002c7bb1a094d0e3b53dffa779d0ebdd7265ea37 100644
--- a/chrome/browser/ui/extensions/native_shell_window.h
+++ b/chrome/browser/ui/extensions/native_shell_window.h
@@ -19,13 +19,7 @@ class NativeShellWindow : public BaseWindow {
 
   // Called when the draggable regions are changed.
   virtual void UpdateDraggableRegions(
-      const std::vector<extensions::DraggableRegion>& regions) {}
-
-  // Called when the draggable regions with the old syntax are changed.
-  // TODO(jianli): to be removed after WebKit patch that changes the draggable
-  // region syntax is landed.
-  virtual void UpdateLegacyDraggableRegions(
-      const std::vector<extensions::DraggableRegion>& regions) {}
+      const std::vector<extensions::DraggableRegion>& regions) = 0;
 
   virtual void SetFullscreen(bool fullscreen) = 0;
   virtual bool IsFullscreenOrPending() const = 0;