Fix webkit_tests by adding two more interfaces they expect.

content/public/app/mojo/content_browser_manifest.json

 {
   "manifest_version": 1,
   "name": "exe:content_browser",
   "process-group": "browser",
   "display_name": "Content Browser",
   "capabilities": {
     // Remove this once http://crbug.com/632818 is fixed.
     "provided": {
       "all_interfaces": [ "*" ],
       "web": [
         "blink::mojom::BackgroundSyncService",
+        "blink::mojom::BroadcastChannelProvider",
         "blink::mojom::BudgetService",
         "blink::mojom::MimeRegistry",
         "blink::mojom::NotificationService",
+        "blink::mojom::OffscreenCanvasFrameReceiver",
         "blink::mojom::OffscreenCanvasSurface",
         "blink::mojom::PermissionService",
         "blink::mojom::WebSocket",
         "content::mojom::LayoutTestBluetoothFakeAdapterSetter",
         "content::mojom::StoragePartitionService",
         "content::mojom::URLLoaderFactory",
         "device::BatteryMonitor",
         "device::mojom::LightSensor",
         "device::mojom::MotionSensor",
         "device::mojom::OrientationSensor",
@@ skipping 21 matching lines @@
       "mojo:file": {
         "interfaces": [
           "leveldb::mojom::LevelDBService",
           "user_service::UserService"
         ]
       },
       "mojo:media": { "classes": [ "all_interfaces" ] }
     }
   }
 }