Begin to enable extension APIs in Extension Service Worker.

content/child/blink_platform_impl.h

Index: content/child/blink_platform_impl.h
diff --git a/content/child/blink_platform_impl.h b/content/child/blink_platform_impl.h
index a4fdf39f3c37d6d809758cd3862b7a99b70c274d..16a87ce2e69baab3da2a0bc2d9b0f0448c601e58 100644
--- a/content/child/blink_platform_impl.h
+++ b/content/child/blink_platform_impl.h
@@ -123,6 +123,8 @@ class CONTENT_EXPORT BlinkPlatformImpl
       const blink::WebSize& cumulative_scroll) override;
   void didStartWorkerThread() override;
   void willStopWorkerThread() override;
+  bool allowScriptExtensionForServiceWorker(
+      const blink::WebURL& script_url) override;
   blink::WebCrypto* crypto() override;
   blink::WebGeofencingProvider* geofencingProvider() override;
   blink::WebNotificationManager* notificationManager() override;