Refactors building the system menu model into a common place

chrome/browser/ui/views/frame/browser_desktop_root_window_host_win.h

Index: chrome/browser/ui/views/frame/browser_desktop_root_window_host_win.h
diff --git a/chrome/browser/ui/views/frame/browser_desktop_root_window_host_win.h b/chrome/browser/ui/views/frame/browser_desktop_root_window_host_win.h
index f1545b4152fce656fcd220971ef3ce757c815b71..abf84cd28aea00eda0742fe644a94454e46aea29 100644
--- a/chrome/browser/ui/views/frame/browser_desktop_root_window_host_win.h
+++ b/chrome/browser/ui/views/frame/browser_desktop_root_window_host_win.h
@@ -14,6 +14,7 @@ class BrowserView;
 
 namespace views {
 class DesktopNativeWidgetAura;
+class NativeMenuWin;
 }
 
 class BrowserDesktopRootWindowHostWin : public BrowserDesktopRootWindowHost,
@@ -28,9 +29,12 @@ class BrowserDesktopRootWindowHostWin : public BrowserDesktopRootWindowHost,
   virtual ~BrowserDesktopRootWindowHostWin();
 
  private:
+  views::NativeMenuWin* GetSystemMenu();
+
   // Overridden from BrowserDesktopRootWindowHost:
   virtual DesktopRootWindowHost* AsDesktopRootWindowHost() OVERRIDE;
   virtual int GetMinimizeButtonOffset() const OVERRIDE;
+  virtual bool UsesNativeSystemMenu() const OVERRIDE;
 
   // Overridden from DesktopRootWindowHostWin:
   virtual int GetInitialShowState() const OVERRIDE;
@@ -52,6 +56,9 @@ class BrowserDesktopRootWindowHostWin : public BrowserDesktopRootWindowHost,
 
   MinimizeButtonMetrics minimize_button_metrics_;
 
+  // The wrapped system menu itself.
+  scoped_ptr<views::NativeMenuWin> system_menu_;
+
   DISALLOW_COPY_AND_ASSIGN(BrowserDesktopRootWindowHostWin);
 };