Fix missing backing store in Linux.

chrome/browser/tab_contents/web_contents_view_mac.h

 // Copyright (c) 2009 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_TAB_CONTENTS_WEB_CONTENTS_VIEW_MAC_H_
 #define CHROME_BROWSER_TAB_CONTENTS_WEB_CONTENTS_VIEW_MAC_H_
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/gfx/size.h"
@@ skipping 39 matching lines @@
   virtual void Invalidate();
   virtual void SizeContents(const gfx::Size& size);
   virtual void FindInPage(const Browser& browser,
                           bool find_next, bool forward_direction);
   virtual void HideFindBar(bool end_session);
   virtual bool GetFindBarWindowInfo(gfx::Point* position,
                                     bool* fully_visible) const;
   virtual void SetInitialFocus();
   virtual void StoreFocus();
   virtual void RestoreFocus();
+  virtual void SetChildSize(RenderWidgetHostView* rwh_view);
 
   // Backend implementation of RenderViewHostDelegate::View.
   virtual RenderWidgetHostView* CreateNewWidgetInternal(int route_id,
                                                         bool activatable);
   virtual void ShowCreatedWidgetInternal(RenderWidgetHostView* widget_host_view,
                                          const gfx::Rect& initial_pos);
   virtual void ShowContextMenu(const ContextMenuParams& params);
   virtual void StartDragging(const WebDropData& drop_data);
   virtual void UpdateDragCursor(bool is_drop_target);
   virtual void TakeFocus(bool reverse);
@@ skipping 24 matching lines @@
   NotificationRegistrar registrar_;
 
   // Used to render the sad tab. This will be non-NULL only when the sad tab is
   // visible.
   scoped_nsobject<SadTabView> sad_tab_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsViewMac);
 };
 
 #endif  // CHROME_BROWSER_TAB_CONTENTS_WEB_CONTENTS_VIEW_MAC_H_