Add a way to fetch window frame metrics from NativeShellWindow

chrome/browser/ui/cocoa/extensions/native_app_window_cocoa.mm

 // 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.
 
 #include "chrome/browser/ui/cocoa/extensions/native_app_window_cocoa.h"
 
 #include "base/mac/mac_util.h"
 #include "base/sys_string_conversions.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/cocoa/browser_window_utils.h"
@@ skipping 637 matching lines @@
   } else {
     [NSApp cancelUserAttentionRequest:attention_request_id_];
     attention_request_id_ = 0;
   }
 }
 
 bool NativeAppWindowCocoa::IsAlwaysOnTop() const {
   return false;
 }
 
+gfx::Insets NativeAppWindowCocoa::GetFrameInsets() const {
+  return gfx::Insets();
+}
+
 void NativeAppWindowCocoa::WindowWillClose() {
   [window_controller_ setAppWindow:NULL];
   shell_window_->OnNativeWindowChanged();
   shell_window_->OnNativeClose();
 }
 
 void NativeAppWindowCocoa::WindowDidBecomeKey() {
   content::RenderWidgetHostView* rwhv =
       web_contents()->GetRenderWidgetHostView();
   if (rwhv)
@@ skipping 61 matching lines @@
   CHECK(!window || [window isKindOfClass:[ShellNSWindow class]]);
   return static_cast<ShellNSWindow*>(window);
 }
 
 // static
 NativeAppWindow* NativeAppWindow::Create(
     ShellWindow* shell_window,
     const ShellWindow::CreateParams& params) {
   return new NativeAppWindowCocoa(shell_window, params);
 }