Adding ViroKit. Needs AWSCore :(

mobile/ios/ViroKit.framework/Headers/VROFrameScheduler.h

@@ -0,0 +1,77 @@
+//
+//  VROFrameScheduler.h
+//  ViroRenderer
+//
+//  Created by Raj Advani on 4/5/17.
+//  Copyright © 2017 Viro Media. All rights reserved.
+//
+
+#ifndef VROFrameScheduler_h
+#define VROFrameScheduler_h
+
+#include "VROFrameTimer.h"
+#include <functional>
+#include <queue>
+#include <mutex>
+#include <string>
+#include <set>
+
+struct VROFrameTask {
+    std::string key;
+    std::function<void()> functor;
+};
+
+/*
+ Schedules tasks to be run on the rendering thread. Unlike 
+ VROPlatformDispatchRenderer, these tasks are run in a time-limited
+ queue; they are scheduled to run only when time is available in
+ the current frame. Time remaining in a frame is determined by a
+ set milliseconds-per-frame (mpf) target.
+ */
+class VROFrameScheduler {
+    
+public:
+    
+    VROFrameScheduler();
+    virtual ~VROFrameScheduler();
+    
+    /*
+     Schedule a new task to be completed in the time-limited 
+     queue. The key should uniquely identify the task, and is used
+     to de-dupe tasks that are scheduled multiple times.
+     */
+    void scheduleTask(std::string key, std::function<void()> task);
+    
+    /*
+     Process as many tasks as allowed given the remaining frame
+     time.
+     */
+    void processTasks(const VROFrameTimer &timer);
+    
+private:
+    
+    /*
+     The number of frames that have passed, during which we had at
+     lease one task to process but no time to process any.
+     */
+    int _starvationFrameCount;
+    
+    /*
+     Guards the _taskQueue and _queuedTasks set.
+     */
+    std::recursive_mutex _taskQueueMutex;
+    
+    /*
+     The actual queue we use to process tasks in FIFO order.
+     */
+    std::queue<VROFrameTask> _taskQueue;
+    
+    /*
+     Set used to prevent the same task from being queued
+     multiple times, based on its ID.
+     */
+    std::set<std::string> _queuedTasks;
+    
+};
+
+#endif /* VROFrameScheduler_h */