Reland of Messaging: Avoid calling non-thread-safe functions in MessagePort::messageAvailable()

third_party/WebKit/Source/core/dom/MessagePort.cpp

 /*
  * Copyright (C) 2008 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 15 matching lines @@
 
 #include "core/dom/MessagePort.h"
 
 #include <memory>
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptState.h"
 #include "bindings/core/v8/SerializedScriptValue.h"
 #include "bindings/core/v8/SerializedScriptValueFactory.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/ExecutionContext.h"
-#include "core/dom/ExecutionContextTask.h"
 #include "core/dom/TaskRunnerHelper.h"
 #include "core/events/MessageEvent.h"
 #include "core/frame/LocalDOMWindow.h"
 #include "core/workers/WorkerGlobalScope.h"
+#include "platform/CrossThreadFunctional.h"
 #include "platform/wtf/Atomics.h"
 #include "platform/wtf/PtrUtil.h"
 #include "platform/wtf/text/AtomicString.h"
 #include "public/platform/WebString.h"
 
 namespace blink {
 
 MessagePort* MessagePort::Create(ExecutionContext& execution_context) {
   return new MessagePort(execution_context);
 }
 
 MessagePort::MessagePort(ExecutionContext& execution_context)
     : ContextLifecycleObserver(&execution_context),
-      pending_dispatch_task_(0),
-      started_(false),
-      closed_(false) {}
+      task_runner_(TaskRunnerHelper::Get(TaskType::kPostedMessage,
+                                         &execution_context)) {}
 
 MessagePort::~MessagePort() {
   DCHECK(!started_ || !IsEntangled());
 }
 
 void MessagePort::postMessage(ScriptState* script_state,
                               PassRefPtr<SerializedScriptValue> message,
                               const MessagePortArray& ports,
                               ExceptionState& exception_state) {
   if (!IsEntangled())
@@ skipping 48 matching lines @@
 
 // Invoked to notify us that there are messages available for this port.
 // This code may be called from another thread, and so should not call any
 // non-threadsafe APIs (i.e. should not call into the entangled channel or
 // access mutable variables).
 void MessagePort::MessageAvailable() {
   // Don't post another task if there's an identical one pending.
   if (AtomicTestAndSetToOne(&pending_dispatch_task_))
     return;
 
-  DCHECK(GetExecutionContext());
-  // TODO(tzik): Use ParentThreadTaskRunners instead of ExecutionContext here to
-  // avoid touching foreign thread GCed object.
-  GetExecutionContext()->PostTask(
-      TaskType::kPostedMessage, BLINK_FROM_HERE,
-      CreateCrossThreadTask(&MessagePort::DispatchMessages,
-                            WrapCrossThreadWeakPersistent(this)));
+  task_runner_->PostTask(BLINK_FROM_HERE,
+                         CrossThreadBind(&MessagePort::DispatchMessages,
+                                         WrapCrossThreadWeakPersistent(this)));
 }
 
 void MessagePort::start() {
   // Do nothing if we've been cloned or closed.
   if (!IsEntangled())
     return;
 
   DCHECK(GetExecutionContext());
   if (started_)
     return;
@@ skipping 144 matching lines @@
   }
   return port_array;
 }
 
 DEFINE_TRACE(MessagePort) {
   ContextLifecycleObserver::Trace(visitor);
   EventTargetWithInlineData::Trace(visitor);
 }
 
 }  // namespace blink