[Enhanced Bookmark]Upstream image fetching code in android

components/enhanced_bookmarks/bookmark_image_service.h

 // Copyright 2014 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 COMPONENTS_ENHANCED_BOOKMARKS_BOOKMARK_IMAGE_SERVICE_H_
 #define COMPONENTS_ENHANCED_BOOKMARKS_BOOKMARK_IMAGE_SERVICE_H_
 
 #include "base/files/file_path.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/singleton.h"
 #include "components/bookmarks/browser/bookmark_model_observer.h"
@@ skipping 66 matching lines @@
   void BookmarkNodeChildrenReordered(
       bookmarks::BookmarkModel* model,
       const bookmarks::BookmarkNode* node) override;
   void BookmarkAllUserNodesRemoved(bookmarks::BookmarkModel* model,
                                    const std::set<GURL>& removed_urls) override;
 
  protected:
   // Returns true if the image for the page_url is currently being fetched.
   bool IsPageUrlInProgress(const GURL& page_url);
 
-  // Once an image has been retrieved, store the image and notify all the
-  // consumers that were waiting on it.
+  // Stores the image to local storage. If update_bookmarks is true, relates the
+  // corresponding bookmark to image_url.
   void ProcessNewImage(const GURL& page_url,
                        bool update_bookmarks,
                        const gfx::Image& image,
                        const GURL& image_url);
 
   // Sets a new image for a bookmark. If the given page_url is bookmarked and
   // the image is retrieved from the image_url, then the image is locally
   // stored. If update_bookmark is true the URL is also added to the bookmark.
   // This is the only method subclass needs to implement.
   virtual void RetrieveSalientImage(
       const GURL& page_url,
       const GURL& image_url,
       const std::string& referrer,
       net::URLRequest::ReferrerPolicy referrer_policy,
       bool update_bookmark) = 0;
 
   // Retrieves a salient image for a given page_url by downloading the image in
   // one of the bookmark.
   virtual void RetrieveSalientImageForPageUrl(const GURL& page_url);
 
   // PageUrls currently in the progress of being retrieved.
   std::set<GURL> in_progress_page_urls_;
 
   // Cached pointer to the bookmark model.
   EnhancedBookmarkModel* enhanced_bookmark_model_;
 
  private:
-  // Same as SalientImageForUrl(const GURL&, ImageCallback) but can
-  // prevent the network request if fetch_from_bookmark is false.
+  // If fetch_from_web is true, retrieves the salient image via a network
+  // request; else only gets the image from local storage.
   void SalientImageForUrl(const GURL& page_url,
-                          bool fetch_from_bookmark,
+                          bool fetch_from_web,
                           ImageCallback stack_callback);
 
   // Processes the requests that have been waiting on an image.
   void ProcessRequests(const GURL& page_url, const ImageRecord& image);
 
   // Once an image is retrieved this method updates the store with it. Returns
   // the newly formed ImageRecord.  This is typically called on |pool_|, the
   // background sequenced worker pool for this object.
   ImageRecord StoreImage(const gfx::Image& image,
                          const GURL& image_url,
@@ skipping 46 matching lines @@
 
   // The worker pool to enqueue the requests onto.
   scoped_refptr<base::SequencedWorkerPool> pool_;
   DISALLOW_COPY_AND_ASSIGN(BookmarkImageService);
 };
 
 }  // namespace enhanced_bookmarks
 
 #endif  // COMPONENTS_ENHANCED_BOOKMARKS_BOOKMARK_IMAGE_SERVICE_H_