Remove dead code

chrome/browser/history/top_sites.h

 // 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.
 
 #ifndef CHROME_BROWSER_HISTORY_TOP_SITES_H_
 #define CHROME_BROWSER_HISTORY_TOP_SITES_H_
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
-#include "chrome/browser/common/cancelable_request.h"
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/history/history_types.h"
 #include "components/history/core/common/thumbnail_score.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/image/image.h"
 
 class GURL;
 class Profile;
 
 namespace base {
@@ skipping 91 matching lines @@
   // thread.
   virtual bool IsBlacklisted(const GURL& url) = 0;
 
   // Clear the blacklist. Should be called from the UI thread.
   virtual void ClearBlacklistedURLs() = 0;
 
   // Shuts down top sites.
   virtual void Shutdown() = 0;
 
   // Query history service for the list of available thumbnails. Returns the
-  // handle for the request, or NULL if a request could not be made.
-  // Public only for testing purposes.
-  virtual CancelableRequestProvider::Handle StartQueryForMostVisited() = 0;
+  // task id for the request, or |base::CancelableTaskTracker::kBadTaskId| if a
+  // request could not be made. Public only for testing purposes.
+  virtual base::CancelableTaskTracker::TaskId StartQueryForMostVisited() = 0;
 
   // Returns true if the given URL is known to the top sites service.
   // This function also returns false if TopSites isn't loaded yet.
   virtual bool IsKnownURL(const GURL& url) = 0;
 
   // Follows the cached redirect chain to convert any URL to its
   // canonical version. If no redirect chain is known for the URL,
   // return it without modification.
   virtual const std::string& GetCanonicalURLString(const GURL& url) const = 0;
 
@@ skipping 40 matching lines @@
 
 #if defined(OS_ANDROID)
 extern const TopSites::PrepopulatedPage kPrepopulatedPages[1];
 #else
 extern const TopSites::PrepopulatedPage kPrepopulatedPages[2];
 #endif
 
 }  // namespace history
 
 #endif  // CHROME_BROWSER_HISTORY_TOP_SITES_H_