Add histogram for how tab closing time. Did some cleanup along the way.

chrome/browser/extensions/extension_host.h

 // Copyright (c) 2006-2009 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_EXTENSIONS_EXTENSION_HOST_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_HOST_H_
 
 #include <string>
 
 #include "base/scoped_ptr.h"
@@ skipping 80 matching lines @@
 
   // RenderViewHostDelegate implementation.
   virtual RenderViewHostDelegate::View* GetViewDelegate();
   virtual const GURL& GetURL() const { return url_; }
   virtual void RenderViewCreated(RenderViewHost* render_view_host);
   virtual ViewType::Type GetRenderViewType() const;
   virtual int GetBrowserWindowID() const;
   virtual void RenderViewGone(RenderViewHost* render_view_host);
   virtual void DidNavigate(RenderViewHost* render_view_host,
                            const ViewHostMsg_FrameNavigate_Params& params);
-  virtual void DidStopLoading(RenderViewHost* render_view_host);
+  virtual void DidStopLoading();
   virtual void DocumentAvailableInMainFrame(RenderViewHost* render_view_host);
 
   virtual WebPreferences GetWebkitPrefs();
   virtual void ProcessDOMUIMessage(const std::string& message,
                                    const Value* content,
                                    int request_id,
                                    bool has_callback);
   virtual void RunJavaScriptMessage(const std::wstring& message,
                                     const std::wstring& default_prompt,
                                     const GURL& frame_url,
@@ skipping 85 matching lines @@
   scoped_ptr<ExtensionFunctionDispatcher> extension_function_dispatcher_;
 
   // Only EXTENSION_TOOLSTRIP and EXTENSION_BACKGROUND_PAGE are used here,
   // others are not hostd by ExtensionHost.
   ViewType::Type extension_host_type_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionHost);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_HOST_H_