cc: add RingBuffer class for timestamp storing in FrameRateCounter

cc/layer_tree_host_impl.cc

Index: cc/layer_tree_host_impl.cc
diff --git a/cc/layer_tree_host_impl.cc b/cc/layer_tree_host_impl.cc
index 22995bbe4c8ad0f02295c5c6c3ec86bc3c6ffe4d..20569d235f3ec9b2851d1c5b49f01785322ce8bf 100644
--- a/cc/layer_tree_host_impl.cc
+++ b/cc/layer_tree_host_impl.cc
@@ -785,7 +785,7 @@ void LayerTreeHostImpl::drawLayers(FrameData& frame)
     // FIXME: use the frame begin time from the overall compositor scheduler.
     // This value is currently inaccessible because it is up in Chromium's
     // RenderWidget.
-    m_fpsCounter->markBeginningOfFrame(base::TimeTicks::Now());
+    m_fpsCounter->saveTimeStamp(base::TimeTicks::Now());
 
     if (m_debugState.showHudRects())
         m_debugRectHistory->saveDebugRectsForCurrentFrame(rootLayer(), *frame.renderSurfaceLayerList, frame.occludingScreenSpaceRects, frame.nonOccludingScreenSpaceRects, m_debugState);
@@ -835,8 +835,6 @@ const RendererCapabilities& LayerTreeHostImpl::rendererCapabilities() const
 bool LayerTreeHostImpl::swapBuffers()
 {
     DCHECK(m_renderer);
-
-    m_fpsCounter->markEndOfFrame();
     return m_renderer->swapBuffers();
 }