service worker: Simplify WorkerFetchContext's controller state.

It was using two data members to determine if there was a controller.
It only needs one.

Minor cleanup for the linked bug.

Bug: 850839
Change-Id: I1d816453047721d79503d47defc8f8cb3e25c7d9
Reviewed-on: https://chromium-review.googlesource.com/1103981
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Reviewed-by: Tsuyoshi Horo <horo@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567976}

content/common/service_worker/service_worker_provider.mojom

@@ -58,17 +58,14 @@ struct ServiceWorkerProviderHostInfo {
 // ServiceWorkerWorkerClient represents a service worker client that is a worker
 // (i.e., a shared worker or dedicated worker). We use this interface to let the
 // WorkerFetchContextImpl in the worker thread know about the change of
-// controlling service worker by calling SetControllerServiceWorker() from the
+// controlling service worker by calling OnControllerChanged() from the
 // ServiceWorkerProviderContext in the main thread of the renderer process.
 //
 // TODO(horo): We should implement ServiceWorkerProvider in the worker thread
-// instead of using this interface to support WorkerNavigator.serviceWorker
-// when we can make the worker thread totally independent from the main thread.
-// Currently we handle synchronous resource loading such as importScripts() and
-// synchronous XHR in the main thread. So we need to know whether the worker is
-// controlled by a service worker or not both in the main thread and in the
-// worker thread.
+// instead of using this interface to support WorkerNavigator.serviceWorker.
 interface ServiceWorkerWorkerClient {
-  // Called when the worker is controlled by a new service worker.
-  SetControllerServiceWorker(int64 controller_version_id);
+  // Called when the worker is controlled by a new service worker. This is only
+  // used to let the worker know that we now have a service worker (while there
+  // may or may not have been one previously), but not the other way around.
+  OnControllerChanged();
 };

content/renderer/service_worker/service_worker_provider_context.cc

@@ -302,7 +302,7 @@ void ServiceWorkerProviderContext::SetController(
     for (const auto& worker : state->worker_clients) {
       // This is a Mojo interface call to the (dedicated or shared) worker
       // thread.
-      worker->SetControllerServiceWorker(state->controller->version_id);
+      worker->OnControllerChanged();
     }
   }
   for (blink::mojom::WebFeature feature : used_features)

content/renderer/service_worker/worker_fetch_context_impl.cc

@@ -260,9 +260,7 @@ void WorkerFetchContextImpl::WillSendRequest(blink::WebURLRequest& request) {
 }
 
 bool WorkerFetchContextImpl::IsControlledByServiceWorker() const {
-  return is_controlled_by_service_worker_ ||
-         (controller_version_id_ !=
-          blink::mojom::kInvalidServiceWorkerVersionId);
+  return is_controlled_by_service_worker_;
 }
 
 void WorkerFetchContextImpl::SetIsOnSubframe(bool is_on_sub_frame) {
@@ -351,9 +349,11 @@ int WorkerFetchContextImpl::ApplicationCacheHostID() const {
   return appcache_host_id_;
 }
 
-void WorkerFetchContextImpl::SetControllerServiceWorker(
-    int64_t controller_version_id) {
-  controller_version_id_ = controller_version_id;
+void WorkerFetchContextImpl::OnControllerChanged() {
+  // This function is called if we transition from (no controller) to
+  // (controller), or if the controller changed.
+  set_is_controlled_by_service_worker(true);
+
   if (ServiceWorkerUtils::IsServicificationEnabled())
     ResetServiceWorkerURLLoaderFactory();
 }

content/renderer/service_worker/worker_fetch_context_impl.h

@@ -93,7 +93,7 @@ class CONTENT_EXPORT WorkerFetchContextImpl
   CreateWebSocketHandshakeThrottle() override;
 
   // mojom::ServiceWorkerWorkerClient implementation:
-  void SetControllerServiceWorker(int64_t controller_version_id) override;
+  void OnControllerChanged() override;
 
   // Sets the fetch context status copied from the frame; the parent frame for a
   // dedicated worker, the main frame of the shadow page for a shared worker.
@@ -165,10 +165,6 @@ class CONTENT_EXPORT WorkerFetchContextImpl
   scoped_refptr<base::RefCountedData<blink::mojom::BlobRegistryPtr>>
       blob_registry_;
 
-  // Updated when mojom::ServiceWorkerWorkerClient::SetControllerServiceWorker()
-  // is called from the browser process via mojo IPC.
-  int controller_version_id_ = blink::mojom::kInvalidServiceWorkerVersionId;
-
   scoped_refptr<ThreadSafeSender> thread_safe_sender_;
   std::unique_ptr<blink::WebDocumentSubresourceFilter::Builder>
       subresource_filter_builder_;