[Reland] Post loading tasks on the appropriate WebFrameScheduler's queue

content/child/resource_scheduling_filter.h

 // Copyright (c) 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_RESOURCE_SCHEDULING_FILTER_H_
 #define CONTENT_CHILD_RESOURCE_SCHEDULING_FILTER_H_
 
+#include <map>
+
 #include "base/containers/hash_tables.h"
 #include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
 #include "content/common/content_export.h"
 #include "ipc/message_filter.h"
 
+namespace blink {
+class WebTaskRunner;
+}
+
 namespace content {
 class ResourceDispatcher;
 
 // This filter is used to dispatch resource messages on a specific
 // SingleThreadTaskRunner to facilitate task scheduling.
 class CONTENT_EXPORT ResourceSchedulingFilter : public IPC::MessageFilter {
  public:
   ResourceSchedulingFilter(const scoped_refptr<base::SingleThreadTaskRunner>&
                                main_thread_task_runner,
                            ResourceDispatcher* resource_dispatcher);
 
   // IPC::MessageFilter overrides:
   bool OnMessageReceived(const IPC::Message& message) override;
 
   bool GetSupportedMessageClasses(
       std::vector<uint32>* supported_message_classes) const override;
 
- protected:
+  // Sets the task runner associated with request messages with |id|.
+  // Takes ownership of |web_task_runner|.
+  void SetRequestIdTaskRunner(
+      int id, blink::WebTaskRunner* web_task_runner);
+
+  // Removes the task runner associated with |id|.
+  void ClearRequestIdTaskRunner(int id);
+
+  void DispatchMessage(const IPC::Message& message);
+
+ private:
   ~ResourceSchedulingFilter() override;
 
-  void DispatchMessage(const IPC::Message& message);
+  typedef std::map<int, scoped_ptr<blink::WebTaskRunner>>
+      RequestIdToTaskRunnerMap;
+
+  // This lock guards |request_id_to_task_runner_map_|
+  base::Lock request_id_to_task_runner_map_lock_;
+  RequestIdToTaskRunnerMap request_id_to_task_runner_map_;
 
   scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
   ResourceDispatcher* resource_dispatcher_;  // NOT OWNED
   base::WeakPtrFactory<ResourceSchedulingFilter> weak_ptr_factory_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ResourceSchedulingFilter);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_RESOURCE_SCHEDULING_FILTER_H_