Implement our own GLThread for VR Shell.

ui/gl/android/surface_texture.h

Index: ui/gl/android/surface_texture.h
diff --git a/ui/gl/android/surface_texture.h b/ui/gl/android/surface_texture.h
index 7d1f8527abfdbfbebfdf3c90bafda567c4993b87..3f0d8e1dbb3b7d45680376b8bd46412e2254981d 100644
--- a/ui/gl/android/surface_texture.h
+++ b/ui/gl/android/surface_texture.h
@@ -62,6 +62,9 @@ class GL_EXPORT SurfaceTexture
   // the android API, because scoped_refptr<> calls that quite a bit.
   void ReleaseSurfaceTexture();
 
+  // Set the default buffer size for the surface texture.
+  void SetDefaultBufferSize(int width, int height);
+
   const base::android::JavaRef<jobject>& j_surface_texture() const {
     return j_surface_texture_;
   }