Refactor GL bindings so there is no global GLApi or DriverGL.

ui/gl/gl_stub_api.cc

 // 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.
 
 #include "ui/gl/gl_stub_api.h"
 
 namespace gl {
 
 namespace {
 
 void GenHelper(GLsizei count, GLuint* objects) {
   for (GLsizei i = 0; i < count; ++i)
     objects[i] = i + 1;
 }
 
 }  // anonymous namespace
 
-GLStubApi::GLStubApi()
-    : version_("OpenGL ES 3.0"), extensions_("GL_EXT_framebuffer_object") {}
+GLStubApi::GLStubApi() {}
 
 GLStubApi::~GLStubApi() = default;
 
 GLenum GLStubApi::glCheckFramebufferStatusEXTFn(GLenum target) {
   return GL_FRAMEBUFFER_COMPLETE;
 }
 
 GLuint GLStubApi::glCreateProgramFn(void) {
   return 1;
 }
@@ skipping 263 matching lines @@
   return GL_TRUE;
 }
 
 GLenum GLStubApi::glWaitSyncFn(GLsync sync,
                                GLbitfield flags,
                                GLuint64 timeout) {
   return GL_TRUE;
 }
 
 }  // namespace gl