ServiceWorker: Stop don't send a message before connection established

content/renderer/service_worker/embedded_worker_instance_client_impl.cc

Index: content/renderer/service_worker/embedded_worker_instance_client_impl.cc
diff --git a/content/renderer/service_worker/embedded_worker_instance_client_impl.cc b/content/renderer/service_worker/embedded_worker_instance_client_impl.cc
index 38014c8cc62640fcf7258ef9d588d784c2c0b1c3..15d4801d0e6eb72f9606f3940c9fbb6dfe6a460c 100644
--- a/content/renderer/service_worker/embedded_worker_instance_client_impl.cc
+++ b/content/renderer/service_worker/embedded_worker_instance_client_impl.cc
@@ -27,13 +27,14 @@ void EmbeddedWorkerInstanceClientImpl::Create(
 
 void EmbeddedWorkerInstanceClientImpl::StopWorkerCompleted() {
   DCHECK(embedded_worker_id_);
-  DCHECK(stop_callback_);
+  DCHECK(!stop_callbacks_.empty());
   dispatcher_->UnregisterWorker(embedded_worker_id_.value());
   embedded_worker_id_.reset();
-  stop_callback_.Run();
+  for (auto& callback : stop_callbacks_)

[nhiroki, 2016/12/15 09:53:15]

Generally, it would be preferable to swap a callback list with an empty list
before invoking each callback like [1] because one of the callbacks could mutate
the callback list during the iteration (I think this case is safe though)

[1]
https://chromium.googlesource.com/chromium/src/+/master/content/browser/servi...

[shimazu, 2016/12/19 08:25:12]

Done.

+    callback.Run();

[nhiroki, 2016/12/15 09:53:15]

Do we need to call EmbeddedWorkerRegistry::OnWorkerStopped() multiple times on
the same worker?

[shimazu, 2016/12/19 08:25:12]

No we don't in terms of the chromium IPC, but mojo IPC requires all callbacks
should be called. 

[nhiroki, 2016/12/19 09:21:55]

What happens when EmbeddedWorkerInstance::Start() is called on the browser
process during several mojo-callbacks are invoked here? I'm concerned that 2nd
or subsequent mojo-callbacks could wrongly cancel the start worker attempt.

[shimazu, 2017/01/05 06:02:41]

Sorry for missing the comment. It's an unwelcome situation. I've updated this
patch not to invoke Stop twice.

+  stop_callbacks_.clear();
   TRACE_EVENT0("ServiceWorker",
                "EmbeddedWorkerInstanceClientImpl::StopWorkerCompleted");
-  stop_callback_.Reset();
   wrapper_ = nullptr;
 }
 
@@ -42,6 +43,7 @@ void EmbeddedWorkerInstanceClientImpl::StartWorker(
     mojom::ServiceWorkerEventDispatcherRequest dispatcher_request) {
   DCHECK(ChildThreadImpl::current());
   DCHECK(!wrapper_);
+  DCHECK(!embedded_worker_id_);
   TRACE_EVENT0("ServiceWorker",
                "EmbeddedWorkerInstanceClientImpl::StartWorker");
   embedded_worker_id_ = params.embedded_worker_id;
@@ -61,12 +63,19 @@ void EmbeddedWorkerInstanceClientImpl::StartWorker(
 void EmbeddedWorkerInstanceClientImpl::StopWorker(
     const StopWorkerCallback& callback) {
   DCHECK(ChildThreadImpl::current());
+  // StopWorker is possible to be called before StartWorker().
+  if (!wrapper_) {
+    callback.Run();
+    return;
+  }
   DCHECK(embedded_worker_id_);
-  // StopWorker is possible to be called twice or before StartWorker().
-  if (stop_callback_ || !wrapper_)
+  // StopWorker is possible to be called twice.
+  if (!stop_callbacks_.empty()) {
+    stop_callbacks_.push_back(std::move(callback));
     return;
+  }
   TRACE_EVENT0("ServiceWorker", "EmbeddedWorkerInstanceClientImpl::StopWorker");
-  stop_callback_ = std::move(callback);
+  stop_callbacks_.push_back(std::move(callback));
   dispatcher_->RecordStopWorkerTimer(embedded_worker_id_.value());
   wrapper_->worker()->terminateWorkerContext();
 }