Set version field when changes are made to enhanced bookmarks.

components/enhanced_bookmarks/bookmark_image_service.h

Index: components/enhanced_bookmarks/bookmark_image_service.h
diff --git a/components/enhanced_bookmarks/bookmark_image_service.h b/components/enhanced_bookmarks/bookmark_image_service.h
index 6ca75eb4e39c97e7dc6b5e44b4446a763d7c33da..3816025d702765f4226bd87dfc9fea13f5ddc346 100644
--- a/components/enhanced_bookmarks/bookmark_image_service.h
+++ b/components/enhanced_bookmarks/bookmark_image_service.h
@@ -20,16 +20,18 @@ class BookmarkNode;
 
 namespace enhanced_bookmarks {
 
+class EnhancedBookmarkModel;
+
 // The BookmarkImageService stores salient images for bookmarks.
 class BookmarkImageService : public KeyedService,
                              public BookmarkModelObserver,
                              public base::NonThreadSafe {
  public:
-  explicit BookmarkImageService(const base::FilePath& path,
-                                BookmarkModel* bookmark_model,
-                                scoped_refptr<base::SequencedWorkerPool> pool);
+  BookmarkImageService(const base::FilePath& path,
+                       EnhancedBookmarkModel* enhanced_bookmark_model,
+                       scoped_refptr<base::SequencedWorkerPool> pool);
   BookmarkImageService(scoped_ptr<ImageStore> store,
-                       BookmarkModel* bookmark_model,
+                       EnhancedBookmarkModel* enhanced_bookmark_model,
                        scoped_refptr<base::SequencedWorkerPool> pool);
 
   virtual ~BookmarkImageService();
@@ -100,8 +102,8 @@ class BookmarkImageService : public KeyedService,
   // PageUrls currently in the progress of being retrieved.
   std::set<GURL> in_progress_page_urls_;
 
-  // Cached pointer to the bookmarks model.
-  BookmarkModel* bookmark_model_;  // weak
+  // Cached pointer to the bookmark model.
+  EnhancedBookmarkModel* enhanced_bookmark_model_;
 
  private:
   // Same as SalientImageForUrl(const GURL&, Callback) but can prevent the