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

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/dom/TaskRunnerHelper.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/frame/LocalFrame.h"
 #include "core/workers/WorkerOrWorkletGlobalScope.h"
@@ skipping 69 matching lines @@
 RefPtr<WebTaskRunner> TaskRunnerHelper::Get(TaskType type,
                                             ScriptState* script_state) {
   return Get(type,
              script_state ? ExecutionContext::From(script_state) : nullptr);
 }
 
 RefPtr<WebTaskRunner> TaskRunnerHelper::Get(
     TaskType type,
     WorkerOrWorkletGlobalScope* global_scope) {
   DCHECK(global_scope);
-  // TODO(nhiroki): Add |DCHECK(global_scope->IsContextThread())| here after
-  // https://crbug.com/694925 is fixed.
+  DCHECK(global_scope->IsContextThread());
   return Get(type, global_scope->GetThread());
 }
 
 RefPtr<WebTaskRunner> TaskRunnerHelper::Get(TaskType type,
                                             WorkerThread* worker_thread) {
   switch (type) {
     case TaskType::kDOMManipulation:
     case TaskType::kUserInteraction:
     case TaskType::kNetworking:
     case TaskType::kHistoryTraversal:
@@ skipping 20 matching lines @@
       // TODO(nhiroki): Identify which tasks can be throttled / suspendable and
       // move them into other task runners. See also comments in
       // Get(LocalFrame). (https://crbug.com/670534)
       return worker_thread->GetGlobalScopeScheduler()->UnthrottledTaskRunner();
   }
   NOTREACHED();
   return nullptr;
 }
 
 }  // namespace blink