[MacViews] Enable dragging a window by its caption/draggable areas.

chrome/browser/ui/views/apps/chrome_native_app_window_views_mac.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_VIEWS_APPS_CHROME_NATIVE_APP_WINDOW_VIEWS_MAC_H_
 #define CHROME_BROWSER_UI_VIEWS_APPS_CHROME_NATIVE_APP_WINDOW_VIEWS_MAC_H_
 
 #include "chrome/browser/ui/views/apps/chrome_native_app_window_views.h"
 
 // Mac-specific parts of ChromeNativeAppWindowViews.
@@ skipping 10 matching lines @@
       views::Widget* widget) override;
   views::NonClientFrameView* CreateStandardDesktopAppFrame() override;
   views::NonClientFrameView* CreateNonStandardAppFrame() override;
 
   // ui::BaseWindow implementation.
   void Show() override;
   void ShowInactive() override;
   void FlashFrame(bool flash) override;
 
   // NativeAppWindow implementation.
+  void UpdateDraggableRegions(
+      const std::vector<extensions::DraggableRegion>& regions) override;
   // These are used to simulate Mac-style hide/show. Since windows can be hidden
   // and shown using the app.window API, this sets is_hidden_with_app_ to
   // differentiate the reason a window was hidden.
   void ShowWithApp() override;
   void HideWithApp() override;
 
  private:
   // Whether this window last became hidden due to a request to hide the entire
   // app, e.g. via the dock menu or Cmd+H. This is set by Hide/ShowWithApp.
   bool is_hidden_with_app_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeNativeAppWindowViewsMac);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_APPS_CHROME_NATIVE_APP_WINDOW_VIEWS_MAC_H_