Introduce WebTaskRunner Patch 1/5

public/platform/WebThread.h

 /*
  * Copyright (C) 2011 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:
  *
  * 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
@@ skipping 16 matching lines @@
 
 #include "WebCommon.h"
 #include <stdint.h>
 
 #ifdef INSIDE_BLINK
 #include "wtf/Functional.h"
 #endif
 
 namespace blink {
 class WebScheduler;
+class WebTaskRunner;
 class WebTraceLocation;
 
 // Always an integer value.
 typedef uintptr_t PlatformThreadId;
 
 // Provides an interface to an embedder-defined thread implementation.
 //
 // Deleting the thread blocks until all pending, non-delayed tasks have been
 // run.
 class BLINK_PLATFORM_EXPORT WebThread {
@@ skipping 15 matching lines @@
     class BLINK_PLATFORM_EXPORT TaskObserver {
     public:
         virtual ~TaskObserver() { }
         virtual void willProcessTask() = 0;
         virtual void didProcessTask() = 0;
     };
 
     // postTask() and postDelayedTask() take ownership of the passed Task
     // object. It is safe to invoke postTask() and postDelayedTask() from any
     // thread.
+    // TODO(alexclarke): Remove postTask & postDelayedTask.
     virtual void postTask(const WebTraceLocation&, Task*) = 0;
     virtual void postDelayedTask(const WebTraceLocation&, Task*, long long delayMs) = 0;
 
+    // Returns a WebTaskRunner bound to the underlying scheduler's default task queue.
+    virtual WebTaskRunner* taskRunner() { return nullptr; }
+
     virtual bool isCurrentThread() const = 0;
     virtual PlatformThreadId threadId() const { return 0; }
 
     virtual void addTaskObserver(TaskObserver*) { }
     virtual void removeTaskObserver(TaskObserver*) { }
 
     // Returns the scheduler associated with the thread.
     virtual WebScheduler* scheduler() const = 0;
 
     virtual ~WebThread() { }
 
 #ifdef INSIDE_BLINK
     // Helpers for posting bound functions as tasks.
     void postTask(const WebTraceLocation&, PassOwnPtr<Function<void()>>);
     void postDelayedTask(const WebTraceLocation&, PassOwnPtr<Function<void()>>, long long delayMs);
 #endif
 };
 
 } // namespace blink
 
 #endif