Add a way to fetch window frame metrics from NativeShellWindow

chrome/browser/ui/extensions/native_shell_window.h

 // Copyright (c) 2012 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_EXTENSIONS_NATIVE_SHELL_WINDOW_H_
 #define CHROME_BROWSER_UI_EXTENSIONS_NATIVE_SHELL_WINDOW_H_
 
 #include "chrome/browser/ui/extensions/shell_window.h"
 #include "chrome/browser/ui/base_window.h"
+#include "ui/gfx/insets.h"
 
 // This is an interface to a native implementation of a shell window, used for
 // new-style packaged apps. Shell windows contain a web contents, but no tabs
 // or URL bar.
 class NativeShellWindow : public BaseWindow {
  public:
   // Used by ShellWindow to instantiate the platform-specific ShellWindow code.
   static NativeShellWindow* Create(ShellWindow* window,
                                    const ShellWindow::CreateParams& params);
 
@@ skipping 12 matching lines @@
 
   // Allows the window to handle unhandled keyboard messages coming back from
   // the renderer.
   virtual void HandleKeyboardEvent(
       const content::NativeWebKeyboardEvent& event) = 0;
 
   // TODO(jianli): once http://crbug.com/123007 is fixed, we'll no longer need
   // this.
   virtual void RenderViewHostChanged() = 0;
 
+  // Returns the difference between the window bounds (including titlebar and
+  // borders) and the content bounds, if any.
+  virtual gfx::Insets GetFrameInsets() const = 0;
+
   virtual ~NativeShellWindow() {}
 };
 
 #endif  // CHROME_BROWSER_UI_EXTENSIONS_NATIVE_SHELL_WINDOW_H_