[WIP] [service worker] Fix detach controller and fallback to network mechanism

content/child/service_worker/service_worker_provider_context.cc

Index: content/child/service_worker/service_worker_provider_context.cc
diff --git a/content/child/service_worker/service_worker_provider_context.cc b/content/child/service_worker/service_worker_provider_context.cc
index 44e567a65f8b12a8bcd72e4a6122114711747b04..ffabed0fe042736fc6d5e26f728fedefc95e252b 100644
--- a/content/child/service_worker/service_worker_provider_context.cc
+++ b/content/child/service_worker/service_worker_provider_context.cc
@@ -57,6 +57,8 @@ class ServiceWorkerProviderContext::ControlleeDelegate
   void SetController(
       scoped_ptr<ServiceWorkerHandleReference> controller) override {
     DCHECK(registration_);
+    DCHECK(!controller ||
+           controller->handle_id() != kInvalidServiceWorkerHandleId);
     controller_ = controller.Pass();
   }