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

chrome/browser/extensions/extension_host.cc

 // 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.
 
 #include "chrome/browser/extensions/extension_host.h"
 
 #include <list>
 
 #include "app/resource_bundle.h"
 #include "base/message_loop.h"
@@ skipping 276 matching lines @@
   while (pos != std::string::npos) {
     css.replace(pos, 12, hex_color_string);
     pos = css.find(kToolstripTextColorSubstitution);
   }
 
   // As a toolstrip, inject our toolstrip CSS to make it easier for toolstrips
   // to blend in with the chrome UI.
   render_view_host()->InsertCSSInWebFrame(L"", css, "ToolstripThemeCSS");
 }
 
-void ExtensionHost::DidStopLoading(RenderViewHost* render_view_host) {
+void ExtensionHost::DidStopLoading() {
   bool notify = !did_stop_loading_;
   did_stop_loading_ = true;
   if (extension_host_type_ == ViewType::EXTENSION_TOOLSTRIP ||
       extension_host_type_ == ViewType::EXTENSION_MOLE ||
       extension_host_type_ == ViewType::EXTENSION_POPUP) {
 #if defined(TOOLKIT_VIEWS)
     if (view_.get())
       view_->DidStopLoading();
 #endif
   }
@@ skipping 207 matching lines @@
     window_id = ExtensionTabUtil::GetWindowId(
         const_cast<ExtensionHost* >(this)->GetBrowser());
   } else if (extension_host_type_ == ViewType::EXTENSION_BACKGROUND_PAGE) {
     // Background page is not attached to any browser window, so pass -1.
     window_id = -1;
   } else {
     NOTREACHED();
   }
   return window_id;
 }