Implement SkGLContext swapBuffers with fence syncs

bench/nanobenchAndroid.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "nanobenchAndroid.h"
 
 #include "AnimationContext.h"
@@ skipping 24 matching lines @@
 }
 
 void HWUITarget::endTiming() {
     this->renderer.finishDrawing();
 }
 
 void HWUITarget::fence() {
     this->renderer.proxy->fence();
 }
 
-bool HWUITarget::needsFrameTiming() const {
+bool HWUITarget::needsFrameTiming(int* frameLag) const {
+    extern int FLAGS_gpuFrameLag;
+    *frameLag = FLAGS_gpuFrameLag;
     return true;
 }
 
 bool HWUITarget::init(SkImageInfo info, Benchmark* bench) {
     this->renderer.initialize({bench->getSize().x(), bench->getSize().y()});
     return true;
 }
 
 bool HWUITarget::capturePixels(SkBitmap* bmp) {
     return this->renderer.capturePixels(bmp);
 }