Fix missing backing store in Linux.

chrome/browser/tab_contents/web_contents_view_mac.mm

 // Copyright (c) 2006-2008 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/tab_contents/web_contents_view_mac.h"
 
 #include "chrome/browser/browser.h" // TODO(beng): this dependency is awful.
 #include "chrome/browser/cocoa/sad_tab_view.h"
 #include "chrome/browser/renderer_host/render_widget_host.h"
 #include "chrome/browser/renderer_host/render_widget_host_view_mac.h"
@@ skipping 139 matching lines @@
 }
 
 void WebContentsViewMac::StoreFocus() {
   // TODO(port)
 }
 
 void WebContentsViewMac::RestoreFocus() {
   // TODO(port)
 }
 
+void WebContentsView::SetChildSize(RenderWidgetHostView* rwh_view) {
+  rwh_view->SetSize(GetContainerSize());
+}
+
 void WebContentsViewMac::UpdateDragCursor(bool is_drop_target) {
   NOTIMPLEMENTED();
 }
 
 void WebContentsViewMac::TakeFocus(bool reverse) {
   [cocoa_view_.get() becomeFirstResponder];
 }
 
 void WebContentsViewMac::HandleKeyboardEvent(
     const NativeWebKeyboardEvent& event) {
@@ skipping 111 matching lines @@
 }
 
 - (void)paste:(id)sender {
   webContentsView_->web_contents()->Paste();
 }
 
 // Tons of stuff goes here, where we grab events going on in Cocoaland and send
 // them into the C++ system. TODO(avi): all that jazz
 
 @end