Revert of Clear SDCH information on "Clear browsing data" path.

chrome/browser/net/sdch_dictionary_fetcher.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.
 
 // Support modularity by calling to load a new SDCH filter dictionary.
 // Note that this sort of calling can't be done in the /net directory, as it has
 // no concept of the HTTP cache (which is only visible at the browser level).
 
 #ifndef CHROME_BROWSER_NET_SDCH_DICTIONARY_FETCHER_H_
 #define CHROME_BROWSER_NET_SDCH_DICTIONARY_FETCHER_H_
@@ skipping 19 matching lines @@
       public base::NonThreadSafe {
  public:
   // Consumer must guarantee that the SdchManager pointer outlives
   // this object.  The current implementation guarantees this by
   // the SdchManager owning this object.
   SdchDictionaryFetcher(net::SdchManager* manager,
                         net::URLRequestContextGetter* context);
   virtual ~SdchDictionaryFetcher();
 
   // Implementation of SdchFetcher class.
+  // This method gets the requested dictionary, and then calls back into the
+  // SdchManager class with the dictionary's text.
   virtual void Schedule(const GURL& dictionary_url) OVERRIDE;
-  virtual void Cancel() OVERRIDE;
 
  private:
   // Delay in ms between Schedule and actual download.
   // This leaves the URL in a queue, which is de-duped, so that there is less
   // chance we'll try to load the same URL multiple times when a pile of
   // page subresources (or tabs opened in parallel) all suggest the dictionary.
   static const int kMsDelayFromRequestTillDownload = 100;
 
   // Ensure the download after the above delay.
   void ScheduleDelayedRun();
@@ skipping 36 matching lines @@
   std::set<GURL> attempted_load_;
 
   // Store the system_url_request_context_getter to use it when we start
   // fetching.
   scoped_refptr<net::URLRequestContextGetter> context_;
 
   DISALLOW_COPY_AND_ASSIGN(SdchDictionaryFetcher);
 };
 
 #endif  // CHROME_BROWSER_NET_SDCH_DICTIONARY_FETCHER_H_