Tweaks to improve memory consumption by TopSites. The biggest culprit

chrome/browser/history/top_sites.h

 // Copyright (c) 2010 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_
 #pragma once
 
-#include <map>
+#include <list>
 #include <set>
 #include <string>
-#include <vector>
 
 #include "base/basictypes.h"
 #include "base/gtest_prod_util.h"
 #include "base/lock.h"
+#include "base/time.h"
 #include "base/timer.h"
 #include "base/ref_counted.h"
 #include "base/ref_counted_memory.h"
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/cancelable_request.h"
 #include "chrome/browser/history/history_types.h"
 #include "chrome/browser/history/history.h"
 #include "chrome/browser/history/page_usage_data.h"
 #include "chrome/common/notification_service.h"
 #include "chrome/common/thumbnail_score.h"
@@ skipping 111 matching lines @@
   // URLs appearing in both old and new lists but having different indices will
   // have their index into "new" be put into |moved_urls|.
   static void DiffMostVisited(const MostVisitedURLList& old_list,
                               const MostVisitedURLList& new_list,
                               TopSitesDelta* delta);
 
  private:
   friend class base::RefCountedThreadSafe<TopSites>;
   friend class TopSitesTest;
 
+  typedef std::pair<GURL, Images> TempImage;
+  typedef std::list<TempImage> TempImages;
+
   // Enumeration of the possible states history can be in.
   enum HistoryLoadState {
     // We're waiting for history to finish loading.
     HISTORY_LOADING,
 
     // History finished loading and we need to migrate top sites out of history.
     HISTORY_MIGRATING,
 
     // History is loaded.
     HISTORY_LOADED
@@ skipping 26 matching lines @@
   // returned by HistoryService.
   bool SetPageThumbnailEncoded(const GURL& url,
                                const RefCountedBytes* thumbnail,
                                const ThumbnailScore& score);
 
   // Encodes the bitmap to bytes for storage to the db. Returns true if the
   // bitmap was successfully encoded.
   static bool EncodeBitmap(const SkBitmap& bitmap,
                            scoped_refptr<RefCountedBytes>* bytes);
 
+  // Removes the cached thumbnail for url. Does nothing if |url| if not cached
+  // in |temp_images_|.
+  void RemoveTemporaryThumbnailByURL(const GURL& url);
+
   // Add a thumbnail for an unknown url. See temp_thumbnails_map_.
   void AddTemporaryThumbnail(const GURL& url,
                              const RefCountedBytes* thumbnail,
                              const ThumbnailScore& score);
 
   // Query history service for the list of available thumbnails.
   void StartQueryForMostVisited();
 
   // Finds the given URL in the redirect chain for the given TopSite, and
   // returns the distance from the destination in hops that the given URL is.
@@ skipping 84 matching lines @@
 
   // Lock used to access |thread_safe_cache_|.
   mutable Lock lock_;
 
   CancelableRequestConsumer cancelable_consumer_;
 
   // Timer that asks history for the top sites. This is used to make sure our
   // data stays in sync with history.
   base::OneShotTimer<TopSites> timer_;
 
+  // The time we started |timer_| at. Only valid if |timer_| is running.
+  base::TimeTicks timer_start_time_;
+
   NotificationRegistrar registrar_;
 
   // The number of URLs changed on the last update.
   size_t last_num_urls_changed_;
 
   // The map of requests for the top sites list. Can only be
   // non-empty at startup. After we read the top sites from the DB, we'll
   // always have a cached list.
   PendingCallbackSet pending_callbacks_;
 
   // Stores thumbnails for unknown pages. When SetPageThumbnail is
   // called, if we don't know about that URL yet and we don't have
   // enough Top Sites (new profile), we store it until the next
   // SetTopSites call.
-  URLToImagesMap temp_thumbnails_map_;
+  TempImages temp_images_;
 
   // Blacklisted and pinned URLs are stored in Preferences.
 
   // Blacklisted URLs. They are filtered out from the list of Top
   // Sites when GetMostVisitedURLs is called. Note that we are still
   // storing all URLs, but filtering on access. It is a dictionary,
   // key is the URL, value is a dummy value. This is owned by the
   // PrefService.
   DictionaryValue* blacklist_;
 
@@ skipping 10 matching lines @@
 
   // Are we loaded?
   bool loaded_;
 
   DISALLOW_COPY_AND_ASSIGN(TopSites);
 };
 
 }  // namespace history
 
 #endif  // CHROME_BROWSER_HISTORY_TOP_SITES_H_