bookmarks: Move BookmarkModelObserver into 'bookmarks' namespace.

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 8b36b704405573893f0a56245b54c3099465d3df..02a61b417cb06df3f72f05d7cf0a9e0f967c51ad 100644
--- a/components/enhanced_bookmarks/bookmark_image_service.h
+++ b/components/enhanced_bookmarks/bookmark_image_service.h
@@ -24,7 +24,7 @@ class EnhancedBookmarkModel;
 
 // The BookmarkImageService stores salient images for bookmarks.
 class BookmarkImageService : public KeyedService,
-                             public BookmarkModelObserver,
+                             public bookmarks::BookmarkModelObserver,
                              public base::NonThreadSafe {
  public:
   BookmarkImageService(const base::FilePath& path,
@@ -48,7 +48,7 @@ class BookmarkImageService : public KeyedService,
   // possible. The callback is always triggered on the main thread.
   void SalientImageForUrl(const GURL& page_url, Callback callback);
 
-  // BookmarkModelObserver methods.
+  // bookmarks::BookmarkModelObserver:
   void BookmarkNodeRemoved(BookmarkModel* model,
                            const BookmarkNode* parent,
                            int old_index,