BackgroundFetchRegistration.abort() should return a Promise.

third_party/WebKit/Source/modules/background_fetch/BackgroundFetchBridge.h

Index: third_party/WebKit/Source/modules/background_fetch/BackgroundFetchBridge.h
diff --git a/third_party/WebKit/Source/modules/background_fetch/BackgroundFetchBridge.h b/third_party/WebKit/Source/modules/background_fetch/BackgroundFetchBridge.h
index 837237db8186649bc8514df41ecf678432d3bb5f..ad8590e5426a46861dc02bd4cc83f8f8bdeb1e07 100644
--- a/third_party/WebKit/Source/modules/background_fetch/BackgroundFetchBridge.h
+++ b/third_party/WebKit/Source/modules/background_fetch/BackgroundFetchBridge.h
@@ -28,12 +28,13 @@ class BackgroundFetchBridge final
   WTF_MAKE_NONCOPYABLE(BackgroundFetchBridge);
 
  public:
-  using UpdateUICallback = Function<void(mojom::blink::BackgroundFetchError)>;
+  using AbortCallback = Function<void(mojom::blink::BackgroundFetchError)>;
   using GetRegistrationCallback =
       Function<void(mojom::blink::BackgroundFetchError,
                     BackgroundFetchRegistration*)>;
   using GetTagsCallback =
       Function<void(mojom::blink::BackgroundFetchError, const Vector<String>&)>;
+  using UpdateUICallback = Function<void(mojom::blink::BackgroundFetchError)>;
 
   static BackgroundFetchBridge* from(ServiceWorkerRegistration*);
   static const char* supplementName();
@@ -49,8 +50,10 @@ class BackgroundFetchBridge final
                 const String& title,
                 std::unique_ptr<UpdateUICallback>);
 
-  // Aborts the active Background Fetch for |tag|. Does not respond.
-  void abort(const String& tag);
+  // Aborts the active Background Fetch for |tag|. Will invoke the |callback|
+  // when the Background Fetch identified by |tag| has been aborted, or could
+  // not be aborted for operational reasons.
+  void abort(const String& tag, std::unique_ptr<AbortCallback>);
 
   // Gets the Background Fetch registration for the given |tag|. Will invoke the
   // |callback| with the Background Fetch registration, which may be a nullptr