Add a WAIT_FOR_GPU_COMPLETION option

Change-Id: I18d526120651676109200bfd5da87cafcd7e3d13
diff --git a/libs/hwui/OpenGLRenderer.cpp b/libs/hwui/OpenGLRenderer.cpp
index 42b246c..76525e0 100644
--- a/libs/hwui/OpenGLRenderer.cpp
+++ b/libs/hwui/OpenGLRenderer.cpp
@@ -20,7 +20,6 @@
 
 #include "DeferredDisplayList.h"
 #include "DisplayListRenderer.h"
-#include "Fence.h"
 #include "GammaFontRenderer.h"
 #include "Patch.h"
 #include "PathTessellator.h"
@@ -563,7 +562,7 @@
     updateLayers();
     flushLayers();
     // Wait for all the layer updates to be executed
-    AutoFence fence;
+    glFinish();
 }
 
 void OpenGLRenderer::markLayersAsBuildLayers() {