[Mac] On pressing Esc key, close Bookmark Bubble without editing.

Dismiss the bubble without updating changes to the node.

BUG=329459
R=asvitkine@chromium.org

TEST=
1. Launch chrome, press "Cmd+Shift+D" to "Show Bookmarks Bar"
2. Navigate to any webpage or new tab & press "Cmd+D" to open bookmark window and then press "Enter" key
3. On the same page, again press "Cmd+D" and change the page name in bookmark bubble window
4. Now press "Esc" key and observe
5. On pressing "Esc" key, bubble should get closed without making any changes to the bookmark

Review URL: https://codereview.chromium.org/592323002

Cr-Commit-Position: refs/heads/master@{#296239}

chrome/browser/ui/cocoa/bookmarks/bookmark_bubble_controller.mm

@@ -250,7 +250,8 @@ using base::UserMetricsAction;
     // |-remove:| calls |-close| so don't do it.
     [self remove:sender];
   } else {
-    [self ok:sender];
+    [self stopPulsingBookmarkButton];
+    [self dismissWithoutEditing:nil];
   }
 }