Switch SnapshotTabHelper to use WebContentsUserData.

chrome/browser/extensions/api/tabs/tabs.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/api/tabs/tabs.h"
 
 #include <algorithm>
 #include <limits>
 #include <vector>
 
@@ skipping 1687 matching lines @@
     error_ = keys::kInternalVisibleTabCaptureError;
     SendResponse(false);
     return;
   }
 
   // Ask the renderer for a snapshot of the tab.
   registrar_.Add(this,
                  chrome::NOTIFICATION_TAB_SNAPSHOT_TAKEN,
                  content::Source<WebContents>(web_contents));
   AddRef();  // Balanced in CaptureVisibleTabFunction::Observe().
-  TabContents::FromWebContents(web_contents)->snapshot_tab_helper()->
-      CaptureSnapshot();
+  SnapshotTabHelper::FromWebContents(web_contents)->CaptureSnapshot();
 }
 
 // If a backing store was not available in CaptureVisibleTabFunction::RunImpl,
 // than the renderer was asked for a snapshot.  Listen for a notification
 // that the snapshot is available.
 void CaptureVisibleTabFunction::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
   DCHECK(type == chrome::NOTIFICATION_TAB_SNAPSHOT_TAKEN);
@@ skipping 136 matching lines @@
   // called for every API call the extension made.
   GotLanguage(language);
 }
 
 void DetectTabLanguageFunction::GotLanguage(const std::string& language) {
   SetResult(Value::CreateStringValue(language.c_str()));
   SendResponse(true);
 
   Release();  // Balanced in Run()
 }