Add V8 platform API to call delayed task.

src/libplatform/default-platform.h

 // Copyright 2013 the V8 project 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 V8_LIBPLATFORM_DEFAULT_PLATFORM_H_
 #define V8_LIBPLATFORM_DEFAULT_PLATFORM_H_
 
+#include <functional>
 #include <map>
 #include <queue>
 #include <vector>
 
 #include "include/v8-platform.h"
 #include "src/base/macros.h"
 #include "src/base/platform/mutex.h"
 #include "src/libplatform/task-queue.h"
 
 namespace v8 {
@@ skipping 12 matching lines @@
 
   void EnsureInitialized();
 
   bool PumpMessageLoop(v8::Isolate* isolate);
 
   // v8::Platform implementation.
   virtual void CallOnBackgroundThread(
       Task* task, ExpectedRuntime expected_runtime) override;
   virtual void CallOnForegroundThread(v8::Isolate* isolate,
                                       Task* task) override;
+  virtual void CallDelayedOnForegroundThread(Isolate* isolate, Task* task,
+                                             double delay_in_seconds) override;
   double MonotonicallyIncreasingTime() override;
 
  private:
   static const int kMaxThreadPoolSize;
 
+  Task* PopTaskInMainThreadQueue(v8::Isolate* isolate);
+  Task* PopTaskInMainThreadDelayedQueue(v8::Isolate* isolate);
+
   base::Mutex lock_;
   bool initialized_;
   int thread_pool_size_;
   std::vector<WorkerThread*> thread_pool_;
   TaskQueue queue_;
   std::map<v8::Isolate*, std::queue<Task*> > main_thread_queue_;
 
+  typedef std::pair<double, Task*> DelayedEntry;
+  std::map<v8::Isolate*,
+           std::priority_queue<DelayedEntry, std::vector<DelayedEntry>,
+                               std::greater<DelayedEntry> > >
+      main_thread_delayed_queue_;
+
   DISALLOW_COPY_AND_ASSIGN(DefaultPlatform);
 };
 
 
 } }  // namespace v8::platform
 
 
 #endif  // V8_LIBPLATFORM_DEFAULT_PLATFORM_H_