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

content/renderer/service_worker/service_worker_script_context.cc

Index: content/renderer/service_worker/service_worker_script_context.cc
diff --git a/content/renderer/service_worker/service_worker_script_context.cc b/content/renderer/service_worker/service_worker_script_context.cc
index 61c83be92c07d65acefa1f12d5b4f623131b33db..74df548b32753e29f51d7d98ba89dfd0d7a958c8 100644
--- a/content/renderer/service_worker/service_worker_script_context.cc
+++ b/content/renderer/service_worker/service_worker_script_context.cc
@@ -253,7 +253,7 @@
   // 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 @@
   // 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 @@
                "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 @@
                "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);
     }
   }