ServiceWorker: Use scheduler's default task queue for posting tasks on main thread

This fixes a task ordering bug between WebMessagePortChannelImpl and
ServiceWorkerScriptContext. The former posts tasks via the Blink
scheduler's default task queue, and the latter was using the MessageLoop
directly. This patch makes tasks from service worker to the main thread
go through the scheduler.

BUG=460833
TEST=http/tests/serviceworker/postmessage-msgport-to-client.html

Review URL: https://codereview.chromium.org/958523002

Cr-Commit-Position: refs/heads/master@{#318022}

content/renderer/service_worker/embedded_worker_context_client.cc

@@ -106,7 +106,7 @@ EmbeddedWorkerContextClient::EmbeddedWorkerContextClient(
       script_url_(script_url),
       worker_devtools_agent_route_id_(worker_devtools_agent_route_id),
       sender_(ChildThreadImpl::current()->thread_safe_sender()),
-      main_thread_proxy_(base::MessageLoopProxy::current()),
+      main_thread_task_runner_(RenderThreadImpl::current()->GetTaskRunner()),
       weak_factory_(this) {
   TRACE_EVENT_ASYNC_BEGIN0("ServiceWorker",
                            "EmbeddedWorkerContextClient::StartingWorkerContext",
@@ -180,7 +180,7 @@ void EmbeddedWorkerContextClient::workerReadyForInspection() {
 }
 
 void EmbeddedWorkerContextClient::workerContextFailedToStart() {
-  DCHECK(main_thread_proxy_->RunsTasksOnCurrentThread());
+  DCHECK(main_thread_task_runner_->RunsTasksOnCurrentThread());
   DCHECK(!script_context_);
 
   Send(new EmbeddedWorkerHostMsg_WorkerScriptLoadFailed(embedded_worker_id_));
@@ -243,7 +243,7 @@ void EmbeddedWorkerContextClient::workerContextDestroyed() {
 
   // Now we should be able to free the WebEmbeddedWorker container on the
   // main thread.
-  main_thread_proxy_->PostTask(
+  main_thread_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&CallWorkerContextDestroyedOnMainThread,
                  embedded_worker_id_));
@@ -355,7 +355,7 @@ void EmbeddedWorkerContextClient::didHandleCrossOriginConnectEvent(
 blink::WebServiceWorkerNetworkProvider*
 EmbeddedWorkerContextClient::createServiceWorkerNetworkProvider(
     blink::WebDataSource* data_source) {
-  DCHECK(main_thread_proxy_->RunsTasksOnCurrentThread());
+  DCHECK(main_thread_task_runner_->RunsTasksOnCurrentThread());
 
   // Create a content::ServiceWorkerNetworkProvider for this data source so
   // we can observe its requests.
@@ -380,7 +380,7 @@ EmbeddedWorkerContextClient::createServiceWorkerNetworkProvider(
 
 blink::WebServiceWorkerProvider*
 EmbeddedWorkerContextClient::createServiceWorkerProvider() {
-  DCHECK(main_thread_proxy_->RunsTasksOnCurrentThread());
+  DCHECK(main_thread_task_runner_->RunsTasksOnCurrentThread());
   DCHECK(provider_context_);
 
   // Blink is responsible for deleting the returned object.

content/renderer/service_worker/embedded_worker_context_client.h

@@ -14,7 +14,7 @@
 #include "url/gurl.h"
 
 namespace base {
-class MessageLoopProxy;
+class SingleThreadTaskRunner;
 class TaskRunner;
 }
 
@@ -130,8 +130,8 @@ class EmbeddedWorkerContextClient
   // TODO: Implement DevTools related method overrides.
 
   int embedded_worker_id() const { return embedded_worker_id_; }
-  base::MessageLoopProxy* main_thread_proxy() const {
-    return main_thread_proxy_.get();
+  base::SingleThreadTaskRunner* main_thread_task_runner() const {
+    return main_thread_task_runner_.get();
   }
   ThreadSafeSender* thread_safe_sender() { return sender_.get(); }
 
@@ -148,7 +148,7 @@ class EmbeddedWorkerContextClient
   const GURL script_url_;
   const int worker_devtools_agent_route_id_;
   scoped_refptr<ThreadSafeSender> sender_;
-  scoped_refptr<base::MessageLoopProxy> main_thread_proxy_;
+  scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
   scoped_refptr<base::TaskRunner> worker_task_runner_;
 
   scoped_ptr<ServiceWorkerScriptContext> script_context_;

content/renderer/service_worker/service_worker_script_context.cc

@@ -253,7 +253,7 @@ void ServiceWorkerScriptContext::PostMessageToDocument(
   // messages for MessagePort (e.g. QueueMessages) are sent from main thread
   // (with thread hopping), so we need to do the same thread hopping here not
   // to overtake those messages.
-  embedded_context_->main_thread_proxy()->PostTask(
+  embedded_context_->main_thread_task_runner()->PostTask(
       FROM_HERE,
       base::Bind(&SendPostMessageToDocumentOnMainThread,
                  make_scoped_refptr(embedded_context_->thread_safe_sender()),
@@ -268,7 +268,7 @@ void ServiceWorkerScriptContext::PostCrossOriginMessageToClient(
   // messages for MessagePort (e.g. QueueMessages) are sent from main thread
   // (with thread hopping), so we need to do the same thread hopping here not
   // to overtake those messages.
-  embedded_context_->main_thread_proxy()->PostTask(
+  embedded_context_->main_thread_task_runner()->PostTask(
       FROM_HERE,
       base::Bind(&SendCrossOriginMessageToClientOnMainThread,
                  make_scoped_refptr(embedded_context_->thread_safe_sender()),
@@ -412,11 +412,12 @@ void ServiceWorkerScriptContext::OnPostMessage(
                "ServiceWorkerScriptContext::OnPostEvent");
   std::vector<WebMessagePortChannelImpl*> ports;
   if (!sent_message_port_ids.empty()) {
-    base::MessageLoopProxy* loop_proxy = embedded_context_->main_thread_proxy();
+    base::SingleThreadTaskRunner* task_runner =
+        embedded_context_->main_thread_task_runner();
     ports.resize(sent_message_port_ids.size());
     for (size_t i = 0; i < sent_message_port_ids.size(); ++i) {
       ports[i] = new WebMessagePortChannelImpl(
-          new_routing_ids[i], sent_message_port_ids[i], loop_proxy);
+          new_routing_ids[i], sent_message_port_ids[i], task_runner);
     }
   }
 
@@ -438,11 +439,12 @@ void ServiceWorkerScriptContext::OnCrossOriginMessageToWorker(
                "ServiceWorkerScriptContext::OnCrossOriginMessageToWorker");
   std::vector<WebMessagePortChannelImpl*> ports;
   if (!sent_message_port_ids.empty()) {
-    base::MessageLoopProxy* loop_proxy = embedded_context_->main_thread_proxy();
+    base::SingleThreadTaskRunner* task_runner =
+        embedded_context_->main_thread_task_runner();
     ports.resize(sent_message_port_ids.size());
     for (size_t i = 0; i < sent_message_port_ids.size(); ++i) {
       ports[i] = new WebMessagePortChannelImpl(
-          new_routing_ids[i], sent_message_port_ids[i], loop_proxy);
+          new_routing_ids[i], sent_message_port_ids[i], task_runner);
     }
   }