Enable BeginFrame scheduling on aura

cc/base/switches.cc

Index: cc/base/switches.cc
diff --git a/cc/base/switches.cc b/cc/base/switches.cc
index c30ab2fe7f0f91fd83349847444fd481e7372d02..02a516a05e0f76f2a3229541924ceb3e29ff2d0c 100644
--- a/cc/base/switches.cc
+++ b/cc/base/switches.cc
@@ -60,6 +60,9 @@ const char kEnablePropertyTreeVerification[] =
 // Disable partial swap which is needed for some OpenGL drivers / emulators.
 const char kUIDisablePartialSwap[] = "ui-disable-partial-swap";
 
+// Use a BeginFrame signal from browser to renderer to schedule rendering.
+const char kEnableBeginFrameScheduling[] = "enable-begin-frame-scheduling";
+
 // Enables the GPU benchmarking extension
 const char kEnableGpuBenchmarking[] = "enable-gpu-benchmarking";