Move static GL binding initialization to //ui/gl/init.

ui/gl/init/gl_initializer.h

 // Copyright 2016 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_INIT_GL_INITIALIZER_H_
 #define UI_GL_INIT_GL_INITIALIZER_H_
 
+#include "ui/gl/gl_implementation.h"
+
 namespace gl {
 namespace init {
 
 // Performs platform dependent one-off GL initialization, calling into the
 // appropriate GLSurface code to initialize it. To perform one-off GL
 // initialization you should use InitializeGLOneOff() or for tests possibly
-// InitializeGLOneOffImplementation() instead of this.
+// InitializeGLOneOffImplementation() instead.
 bool InitializeGLOneOffPlatform();
 
+// Initializes a particular GL implementation.
+bool InitializeStaticGLBindings(GLImplementation implementation);
+
+// Initializes debug logging wrappers for GL bindings.
+void InitializeDebugGLBindings();
+
+// Clears GL bindings for all implementations supported by platform.
+void ClearGLBindingsPlatform();
+
 }  // namespace init
 }  // namespace gl
 
 #endif  // UI_GL_INIT_GL_INITIALIZER_H_