Revert of Move SkGLContext and some GrGLInterface implementations to skgputest module

tools/gpu/gl/null/NullGLContext.h

Index: tools/gpu/gl/null/NullGLContext.h
diff --git a/tools/gpu/gl/null/NullGLContext.h b/tools/gpu/gl/null/NullGLContext.h
deleted file mode 100644
index 16fb9fd1df8b0d776fef6cbacbe5dc158260e676..0000000000000000000000000000000000000000
--- a/tools/gpu/gl/null/NullGLContext.h
+++ /dev/null
@@ -1,17 +0,0 @@
-
-/*
- * Copyright 2011 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-#ifndef NullGLContext_DEFINED
-#define NullGLContext_DEFINED
-
-#include "gl/GLContext.h"
-
-namespace sk_gpu_test {
-GLContext* CreateNullGLContext();
-}  // namespace sk_gpu_test
-
-#endif