Enable GPU pixel buffers on OpenGL ES 3.0 devices

Change-Id: I164d72ccd7a9bf6ae0e3f79dfef50083558937ba
diff --git a/libs/hwui/Caches.h b/libs/hwui/Caches.h
index 18aeeab..54e4138 100644
--- a/libs/hwui/Caches.h
+++ b/libs/hwui/Caches.h
@@ -302,6 +302,8 @@
 
     AssetAtlas assetAtlas;
 
+    bool gpuPixelBuffersEnabled;
+
     // Debug methods
     PFNGLINSERTEVENTMARKEREXTPROC eventMark;
     PFNGLPUSHGROUPMARKEREXTPROC startMark;
@@ -314,6 +316,7 @@
     void initFont();
     void initExtensions();
     void initConstraints();
+    void initStaticProperties();
 
     static void eventMarkNull(GLsizei length, const GLchar* marker) { }
     static void startMarkNull(GLsizei length, const GLchar* marker) { }