Get rid of the last RenderViewHostDelegate usage in chrome.

chrome/browser/extensions/extension_tabs_module.cc

 // 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/extensions/extension_tabs_module.h"
 
 #include <algorithm>
 #include <limits>
 #include <vector>
 
@@ skipping 1509 matching lines @@
     if (!GetTabById(tab_ids[i], profile(), include_incognito(),
                     &browser, NULL, &contents, NULL, &error_))
       return false;
 
     // Don't let the extension remove a tab if the user is dragging tabs around.
     if (!browser->IsTabStripEditable()) {
       error_ = keys::kTabStripNotEditableError;
       return false;
     }
 
-    // Close the tab in this convoluted way, since there's a chance that the tab
-    // is being dragged, or we're in some other nested event loop. This code
-    // path should ensure that the tab is safely closed under such
-    // circumstances, whereas |Browser::CloseTabContents()| does not.
-    RenderViewHost* render_view_host =
-        contents->web_contents()->GetRenderViewHost();
-    render_view_host->GetDelegate()->Close(render_view_host);
+    // There's a chance that the tab is being dragged, or we're in some other
+    // nested event loop. This code path ensures that the tab is safely closed
+    // under such circumstances, whereas |Browser::CloseTabContents()| does not.
+    contents->web_contents()->Close();
   }
   return true;
 }
 
 bool CaptureVisibleTabFunction::GetTabToCapture(
     WebContents** web_contents, TabContentsWrapper** wrapper) {
   Browser* browser = NULL;
   // windowId defaults to "current" window.
   int window_id = extension_misc::kCurrentWindowId;
 
@@ skipping 238 matching lines @@
   // called for every API call the extension made.
   GotLanguage(language);
 }
 
 void DetectTabLanguageFunction::GotLanguage(const std::string& language) {
   result_.reset(Value::CreateStringValue(language.c_str()));
   SendResponse(true);
 
   Release();  // Balanced in Run()
 }