Move SkGLContext and some GrGLInterface implementations to skgputest module

src/gpu/gl/mesa/osmesa_wrapper.h

Index: src/gpu/gl/mesa/osmesa_wrapper.h
diff --git a/src/gpu/gl/mesa/osmesa_wrapper.h b/src/gpu/gl/mesa/osmesa_wrapper.h
deleted file mode 100644
index 70de99376d78935e4d580a8065f991c297be8499..0000000000000000000000000000000000000000
--- a/src/gpu/gl/mesa/osmesa_wrapper.h
+++ /dev/null
@@ -1,16 +0,0 @@
-
-/*
- * Copyright 2013 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-// Older versions of XQuartz have a bug where a header included by osmesa.h
-// defines GL_GLEXT_PROTOTYPES. This will cause a redefinition warning if
-// the file that includes osmesa.h already defined it. XCode 3 uses a version
-// of gcc (4.2.1) that does not support the diagnostic pragma to disable a
-// warning (added in 4.2.4). So we use the system_header pragma to shut GCC
-// up about warnings in osmesa.h
-#pragma GCC system_header
-#include <GL/osmesa.h>