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

third_party/WebKit/Source/web/WebSharedWorkerImpl.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 232 matching lines @@
       createCrossThreadTask(
           &WebSharedWorkerImpl::postMessageToPageInspectorOnMainThread,
           crossThreadUnretained(this), message));
 }
 
 void WebSharedWorkerImpl::postMessageToPageInspectorOnMainThread(
     const String& message) {
   m_workerInspectorProxy->dispatchMessageFromWorker(message);
 }
 
+ParentFrameTaskRunners* WebSharedWorkerImpl::getParentFrameTaskRunners() {
+  return m_parentFrameTaskRunners.get();
+}
+
 void WebSharedWorkerImpl::didCloseWorkerGlobalScope() {
+  // TODO(nhiroki): Replace this with getParentFrameTaskRunners().
+  // (https://crbug.com/667310)
   Platform::current()->mainThread()->getWebTaskRunner()->postTask(
       BLINK_FROM_HERE,
       crossThreadBind(
           &WebSharedWorkerImpl::didCloseWorkerGlobalScopeOnMainThread,
           crossThreadUnretained(this)));
 }
 
 void WebSharedWorkerImpl::didCloseWorkerGlobalScopeOnMainThread() {
   m_client->workerContextClosed();
 
   terminateWorkerThread();
 }
 
 void WebSharedWorkerImpl::didTerminateWorkerThread() {
+  // TODO(nhiroki): Replace this with getParentFrameTaskRunners().
+  // (https://crbug.com/667310)
   Platform::current()->mainThread()->getWebTaskRunner()->postTask(
       BLINK_FROM_HERE,
       crossThreadBind(
           &WebSharedWorkerImpl::didTerminateWorkerThreadOnMainThread,
           crossThreadUnretained(this)));
 }
 
 void WebSharedWorkerImpl::didTerminateWorkerThreadOnMainThread() {
   m_client->workerContextDestroyed();
   // The lifetime of this proxy is controlled by the worker context.
   delete this;
 }
 
 // WorkerLoaderProxyProvider -------------------------------------------------
 
 void WebSharedWorkerImpl::postTaskToLoader(
     const WebTraceLocation& location,
     std::unique_ptr<ExecutionContextTask> task) {
   // TODO(hiroshige,yuryu): Make this not use ExecutionContextTask and
-  // consider using m_mainThreadTaskRunners->get(TaskType::Networking)
+  // consider using m_parentFrameTaskRunners->get(TaskType::Networking)
   // instead.
   m_mainFrame->frame()->document()->postTask(location, std::move(task));
 }
 
 void WebSharedWorkerImpl::postTaskToWorkerGlobalScope(
     const WebTraceLocation& location,
     std::unique_ptr<ExecutionContextTask> task) {
   m_workerThread->postTask(location, std::move(task));
 }
 
@@ skipping 71 matching lines @@
   std::unique_ptr<WorkerThreadStartupData> startupData =
       WorkerThreadStartupData::create(
           m_url, m_loadingDocument->userAgent(), m_mainScriptLoader->script(),
           nullptr, startMode,
           contentSecurityPolicy ? contentSecurityPolicy->headers().get()
                                 : nullptr,
           m_mainScriptLoader->referrerPolicy(), starterOrigin, workerClients,
           m_mainScriptLoader->responseAddressSpace(),
           m_mainScriptLoader->originTrialTokens(), std::move(workerSettings));
 
-  // We have a dummy document here for loading but it doesn't really represent
-  // the document/frame of associated document(s) for this worker. Here we
-  // populate the task runners with null document not to confuse the frame
-  // scheduler (which will end up using the thread's default task runner).
-  m_mainThreadTaskRunners = ParentFrameTaskRunners::create(nullptr);
+  // SharedWorker 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.
+  m_parentFrameTaskRunners = ParentFrameTaskRunners::create(nullptr);
 
   m_loaderProxy = WorkerLoaderProxy::create(this);
   m_workerThread = SharedWorkerThread::create(m_name, m_loaderProxy, *this);
   InspectorInstrumentation::scriptImported(m_loadingDocument.get(),
                                            m_mainScriptLoader->identifier(),
                                            m_mainScriptLoader->script());
   m_mainScriptLoader.clear();
 
   workerThread()->start(std::move(startupData));
   m_workerInspectorProxy->workerThreadCreated(
@@ skipping 41 matching lines @@
   if (devtoolsAgent)
     devtoolsAgent->dispatchOnInspectorBackend(sessionId, callId, method,
                                               message);
 }
 
 WebSharedWorker* WebSharedWorker::create(WebSharedWorkerClient* client) {
   return new WebSharedWorkerImpl(client);
 }
 
 }  // namespace blink