Worker: Provide a way to access parent frame task runners from a worker thread

third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp

Index: third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp
diff --git a/third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp b/third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp
index b3d1850adf7115988cb12ace8c85a4223eb20caa..eb9a78541a351b4a1c5785f1ceacd820d2f72819 100644
--- a/third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp
+++ b/third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp
@@ -38,6 +38,7 @@
 #include "core/dom/MessagePort.h"
 #include "core/inspector/ConsoleMessage.h"
 #include "core/origin_trials/OriginTrials.h"
+#include "core/workers/ParentFrameTaskRunners.h"
 #include "core/workers/WorkerGlobalScope.h"
 #include "core/workers/WorkerThread.h"
 #include "modules/background_sync/SyncEvent.h"
@@ -86,6 +87,7 @@ ServiceWorkerGlobalScopeProxy::~ServiceWorkerGlobalScopeProxy() {
 
 DEFINE_TRACE(ServiceWorkerGlobalScopeProxy) {
   visitor->trace(m_document);
+  visitor->trace(m_parentFrameTaskRunners);
   visitor->trace(m_pendingPreloadFetchEvents);
 }
 
@@ -357,6 +359,11 @@ void ServiceWorkerGlobalScopeProxy::postMessageToPageInspector(
                             crossThreadUnretained(m_embeddedWorker), message));
 }
 
+ParentFrameTaskRunners*
+ServiceWorkerGlobalScopeProxy::getParentFrameTaskRunners() {
+  return m_parentFrameTaskRunners.get();
+}
+
 void ServiceWorkerGlobalScopeProxy::didCreateWorkerGlobalScope(
     WorkerOrWorkletGlobalScope* workerGlobalScope) {
   DCHECK(!m_workerGlobalScope);
@@ -416,7 +423,13 @@ ServiceWorkerGlobalScopeProxy::ServiceWorkerGlobalScopeProxy(
     : m_embeddedWorker(&embeddedWorker),
       m_document(&document),
       m_client(&client),
-      m_workerGlobalScope(nullptr) {}
+      m_workerGlobalScope(nullptr) {
+  // ServiceWorker is never associated with any document's frame. We have a

[falken, 2016/11/28 01:37:44]

"never associated" may be confusing since typically we'd say service worker may
be "associated" with many documents or none at all (indeed the next sentence
implies this). Maybe this comment can be expanded with something like: "Service
worker can sometimes run tasks that are initiated by/associated with a
document's frame but these documents can be from a different process. So we
intentionally populate the task runners with null document in order to use the
thread's default task runner. Note that |m_document| should not be used as it's
a dummy document for loading that doesn't represent the frame of any associated
document."

(same kind of thing for the shared worker comment).

[nhiroki, 2016/11/28 02:26:59]

Updated the comments.

+  // dummy document for loading but it doesn't really represent the frame of
+  // associated document(s). Here we intentionally populate the task runners
+  // with null document that will end up using the thread's default task runner.
+  m_parentFrameTaskRunners = ParentFrameTaskRunners::create(nullptr);
+}
 
 void ServiceWorkerGlobalScopeProxy::detach() {
   m_embeddedWorker = nullptr;