Bug 1317554. Make the notifications that VectorImage sends on draw async. r=aosmond

image/VectorImage.cpp

@@ -985,8 +985,19 @@ VectorImage::CreateSurfaceAndShow(const SVGDrawingParameters& aParams, BackendTy
 
   // Send out an invalidation so that surfaces that are still in use get
   // re-locked. See the discussion of the UnlockSurfaces call above.
-  mProgressTracker->SyncNotifyProgress(FLAG_FRAME_COMPLETE,
-                                       GetMaxSizedIntRect());
+  if (!(aParams.flags & FLAG_ASYNC_NOTIFY)) {
+    mProgressTracker->SyncNotifyProgress(FLAG_FRAME_COMPLETE,
+                                         GetMaxSizedIntRect());
+  } else {
+    NotNull<RefPtr<VectorImage>> image = WrapNotNull(this);
+    NS_DispatchToMainThread(NS_NewRunnableFunction([=]() -> void {
+      RefPtr<ProgressTracker> tracker = image->GetProgressTracker();
+      if (tracker) {
+        tracker->SyncNotifyProgress(FLAG_FRAME_COMPLETE,
+                                    GetMaxSizedIntRect());
+      }
+    }));
+  }
 }