Implementing URL prefix match for history thumbnail cache.

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"
@@ skipping 55 matching lines @@
   // Returns a list of most visited URLs via a callback. This may be invoked on
   // any thread.
   // NOTE: the callback is called immediately if we have the data cached. If
   // data is not available yet, callback will later be posted to the thread
   // called this function.
   virtual void GetMostVisitedURLs(
       const GetMostVisitedURLsCallback& callback) = 0;
 
   // Get a thumbnail for a given page. Returns true iff we have the thumbnail.
   // This may be invoked on any thread.
+  // If an exact thumbnail URL match fails, |prefix_match| specifies whether or
+  // not to try harder by matching the query thumbnail URL as URL prefix (as
+  // defined by UrlIsPrefix()).
   // As this method may be invoked on any thread the ref count needs to be
   // incremented before this method returns, so this takes a scoped_refptr*.
   virtual bool GetPageThumbnail(
-      const GURL& url, scoped_refptr<base::RefCountedMemory>* bytes) = 0;
+      const GURL& url,
+      bool prefix_match,
+      scoped_refptr<base::RefCountedMemory>* bytes) = 0;
 
   // Get a thumbnail score for a given page. Returns true iff we have the
   // thumbnail score.  This may be invoked on any thread. The score will
   // be copied to |score|.
   virtual bool GetPageThumbnailScore(const GURL& url,
                                      ThumbnailScore* score) = 0;
 
   // Get a temporary thumbnail score for a given page. Returns true iff we
   // have the thumbnail score. Useful when checking if we should update a
   // thumbnail for a given page. The score will be copied to |score|.
@@ skipping 70 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_