Take GL version and extensions correctly into account when binding functions

ui/gl/gl_context_stub_with_extensions.h

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UI_GL_GL_CONTEXT_STUB_WITH_EXTENSIONS_H_
+#define UI_GL_GL_CONTEXT_STUB_WITH_EXTENSIONS_H_
+
+#include "ui/gl/gl_context_stub.h"
+
+namespace gfx {
+
+// Lightweight GLContext stub implementation that returns a constructed
+// extensions string.  We use this to create a context that we can use to
+// initialize GL extensions with, without actually creating a platform context.
+class GL_EXPORT GLContextStubWithExtensions : public gfx::GLContextStub {
+ public:
+  GLContextStubWithExtensions() {}
+  virtual std::string GetExtensions() OVERRIDE;
+
+  void AddExtensionsString(const char* extensions);
+  void SetGLVersionString(const char* version_str);
+
+ protected:
+  virtual std::string GetGLVersion() OVERRIDE;
+
+  virtual ~GLContextStubWithExtensions() {}
+
+ private:
+  std::string extensions_;
+  std::string version_str_;
+
+  DISALLOW_COPY_AND_ASSIGN(GLContextStubWithExtensions);
+};
+
+}  // namespace gfx
+
+#endif  // UI_GL_GL_CONTEXT_STUB_WITH_EXTENSIONS_H_