Revert of Revert of Add a WorkerScheduler and a WebThreadImplForWorker

content/child/webthread_base.h

Index: content/child/webthread_base.h
diff --git a/content/child/webthread_base.h b/content/child/webthread_base.h
new file mode 100644
index 0000000000000000000000000000000000000000..5d6ebb9b0f05ff1855116f80870e2d8fda1ad696
--- /dev/null
+++ b/content/child/webthread_base.h
@@ -0,0 +1,80 @@
+// Copyright 2014 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.
+
+#ifndef CONTENT_CHILD_WEBTHREAD_BASE_H_
+#define CONTENT_CHILD_WEBTHREAD_BASE_H_
+
+#include <map>
+
+#include "base/memory/scoped_ptr.h"
+#include "base/threading/thread.h"
+#include "content/common/content_export.h"
+#include "third_party/WebKit/public/platform/WebThread.h"
+
+namespace blink {
+class WebTraceLocation;
+}
+
+namespace content {
+class SingleThreadIdleTaskRunner;
+
+class CONTENT_EXPORT WebThreadBase : public blink::WebThread {
+ public:
+  virtual ~WebThreadBase();
+
+  // blink::WebThread implementation.
+  virtual bool isCurrentThread() const;
+  virtual blink::PlatformThreadId threadId() const = 0;
+
+  virtual void postTask(const blink::WebTraceLocation& location, Task* task);
+  virtual void postDelayedTask(const blink::WebTraceLocation& location,
+                               Task* task,
+                               long long delay_ms);
+  virtual void postIdleTask(const blink::WebTraceLocation& location,
+                            IdleTask* idle_task);
+  virtual void postIdleTaskAfterWakeup(const blink::WebTraceLocation& location,
+                                       IdleTask* idle_task);
+
+  virtual void enterRunLoop();
+  virtual void exitRunLoop();
+
+  virtual void addTaskObserver(TaskObserver* observer);
+  virtual void removeTaskObserver(TaskObserver* observer);
+
+  // Returns the base::Bind-compatible task runner for posting tasks to this
+  // thread. Can be called from any thread.
+  virtual base::SingleThreadTaskRunner* TaskRunner() const = 0;
+
+  // Returns the base::Bind-compatible task runner for posting idle tasks to
+  // this thread. Can be called from any thread.
+  virtual SingleThreadIdleTaskRunner* IdleTaskRunner() const = 0;
+
+ protected:
+  class TaskObserverAdapter;
+
+  WebThreadBase();
+
+  // Returns the underlying MessageLoop for this thread. Only used for entering
+  // and exiting a nested run loop. Only called on the thread that the
+  // WebThread belongs to.
+  virtual base::MessageLoop* MessageLoop() const = 0;
+
+  virtual void AddTaskObserverInternal(
+      base::MessageLoop::TaskObserver* observer);
+  virtual void RemoveTaskObserverInternal(
+      base::MessageLoop::TaskObserver* observer);
+
+  static void RunWebThreadTask(scoped_ptr<blink::WebThread::Task> task);
+  static void RunWebThreadIdleTask(
+      scoped_ptr<blink::WebThread::IdleTask> idle_task,
+      base::TimeTicks deadline);
+
+ private:
+  typedef std::map<TaskObserver*, TaskObserverAdapter*> TaskObserverMap;
+  TaskObserverMap task_observer_map_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_CHILD_WEBTHREAD_BASE_H_