ServiceWorker: Queue worker state changes until Blink is ready for them

Chromium-side part of the following:
https://codereview.chromium.org/247263010/
https://codereview.chromium.org/256723002/

BUG=365252

Review URL: https://codereview.chromium.org/255813003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@266544 0039d316-1c4b-4281-b951-d872f2087c98

content/child/service_worker/service_worker_dispatcher.cc

@@ -198,7 +198,7 @@ void ServiceWorkerDispatcher::OnServiceWorkerStateChanged(
   ServiceWorkerMap::iterator found = service_workers_.find(handle_id);
   if (found == service_workers_.end())
     return;
-  found->second->SetState(state);
+  found->second->OnStateChanged(state);
 }
 
 void ServiceWorkerDispatcher::OnSetCurrentServiceWorker(

content/child/service_worker/web_service_worker_impl.cc

@@ -44,17 +44,31 @@ WebServiceWorkerImpl::~WebServiceWorkerImpl() {
     dispatcher->RemoveServiceWorker(handle_id_);
 }
 
-void WebServiceWorkerImpl::SetState(blink::WebServiceWorkerState new_state) {
-  state_ = new_state;
-  if (!proxy_)
-    return;
-  proxy_->dispatchStateChangeEvent();
+void WebServiceWorkerImpl::OnStateChanged(
+    blink::WebServiceWorkerState new_state) {
+  DCHECK(proxy_);
+  if (proxy_->isReady())
+    ChangeState(new_state);
+  else
+    queued_states_.push_back(new_state);
 }
 
 void WebServiceWorkerImpl::setProxy(blink::WebServiceWorkerProxy* proxy) {
   proxy_ = proxy;
 }
 
+void WebServiceWorkerImpl::proxyReadyChanged() {
+  if (!proxy_->isReady())
+    return;
+  for (std::vector<blink::WebServiceWorkerState>::iterator it =
+           queued_states_.begin();
+       it != queued_states_.end();
+       ++it) {
+    ChangeState(*it);
+  }
+  queued_states_.clear();
+}
+
 blink::WebURL WebServiceWorkerImpl::scope() const {
   return scope_;
 }
@@ -75,4 +89,11 @@ void WebServiceWorkerImpl::postMessage(const WebString& message,
       WebMessagePortChannelImpl::ExtractMessagePortIDs(channels)));
 }
 
+void WebServiceWorkerImpl::ChangeState(blink::WebServiceWorkerState new_state) {
+  DCHECK(proxy_);
+  DCHECK(proxy_->isReady());
+  state_ = new_state;
+  proxy_->dispatchStateChangeEvent();
+}
+
 }  // namespace content

content/child/service_worker/web_service_worker_impl.h

@@ -5,6 +5,8 @@
 #ifndef CONTENT_CHILD_SERVICE_WORKER_WEB_SERVICE_WORKER_IMPL_H_
 #define CONTENT_CHILD_SERVICE_WORKER_WEB_SERVICE_WORKER_IMPL_H_
 
+#include <vector>
+
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "base/strings/string16.h"
@@ -28,9 +30,13 @@ class WebServiceWorkerImpl
                        ThreadSafeSender* thread_safe_sender);
   virtual ~WebServiceWorkerImpl();
 
-  void SetState(blink::WebServiceWorkerState new_state);
+  // Notifies that the service worker's state changed. This function may queue
+  // the state change for later processing, if the proxy is not yet ready to
+  // handle state changes.
+  void OnStateChanged(blink::WebServiceWorkerState new_state);
 
   virtual void setProxy(blink::WebServiceWorkerProxy* proxy);
+  virtual void proxyReadyChanged();
   virtual blink::WebURL scope() const;
   virtual blink::WebURL url() const;
   virtual blink::WebServiceWorkerState state() const;
@@ -38,12 +44,16 @@ class WebServiceWorkerImpl
                            blink::WebMessagePortChannelArray* channels);
 
  private:
+  // Commits the new state internally and notifies the proxy of the change.
+  void ChangeState(blink::WebServiceWorkerState new_state);
+
   const int handle_id_;
   const GURL scope_;
   const GURL url_;
   blink::WebServiceWorkerState state_;
   scoped_refptr<ThreadSafeSender> thread_safe_sender_;
   blink::WebServiceWorkerProxy* proxy_;
+  std::vector<blink::WebServiceWorkerState> queued_states_;
 
   DISALLOW_COPY_AND_ASSIGN(WebServiceWorkerImpl);
 };