MacViews: Don't draw custom frame on Mac

chrome/browser/ui/views/frame/desktop_browser_frame_aura.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_VIEWS_FRAME_DESKTOP_BROWSER_FRAME_AURA_H_
 #define CHROME_BROWSER_UI_VIEWS_FRAME_DESKTOP_BROWSER_FRAME_AURA_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/ui/views/frame/native_browser_frame.h"
@@ skipping 14 matching lines @@
 //  DesktopBrowserFrameAura is a DesktopNativeWidgetAura subclass that provides
 //  the window frame for the Chrome browser window.
 //
 class DesktopBrowserFrameAura : public views::DesktopNativeWidgetAura,
                                 public NativeBrowserFrame {
  public:
   DesktopBrowserFrameAura(BrowserFrame* browser_frame,
                           BrowserView* browser_view);
 
   BrowserView* browser_view() const { return browser_view_; }
+  BrowserFrame* browser_frame() const { return browser_frame_; }
 
  protected:
   ~DesktopBrowserFrameAura() override;
 
   // Overridden from views::DesktopNativeWidgetAura:
   void OnHostClosed() override;
   void InitNativeWidget(const views::Widget::InitParams& params) override;
 
   // Overridden from NativeBrowserFrame:
   views::Widget::InitParams GetWidgetParams() override;
+  bool UseCustomFrame() const override;
   bool UsesNativeSystemMenu() const override;
   int GetMinimizeButtonOffset() const override;
   bool ShouldSaveWindowPlacement() const override;
   void GetWindowPlacement(gfx::Rect* bounds,
                           ui::WindowShowState* show_state) const override;
 
  private:
   // The BrowserView is our ClientView. This is a pointer to it.
   BrowserView* browser_view_;
   BrowserFrame* browser_frame_;
 
   // Owned by the RootWindow.
   BrowserDesktopWindowTreeHost* browser_desktop_window_tree_host_;
 
   scoped_ptr<wm::VisibilityController> visibility_controller_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopBrowserFrameAura);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_FRAME_DESKTOP_BROWSER_FRAME_AURA_H_