Hook ANGLE_request_extension up to the passthrough cmd decoder.

ui/gl/gl_bindings_autogen_mock.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.
 //
 // This file is auto-generated from
 // ui/gl/generate_bindings.py
 // It's formatted by clang-format using chromium coding style:
 //    clang-format -i -style=chromium filename
 // DO NOT EDIT!
 
@@ skipping 1196 matching lines @@
                                          GLsizei samples,
                                          GLenum internalformat,
                                          GLsizei width,
                                          GLsizei height);
 static void GL_BINDING_CALL
 Mock_glRenderbufferStorageMultisampleIMG(GLenum target,
                                          GLsizei samples,
                                          GLenum internalformat,
                                          GLsizei width,
                                          GLsizei height);
+static void GL_BINDING_CALL Mock_glRequestExtensionANGLE(const char* name);
 static void GL_BINDING_CALL Mock_glResumeTransformFeedback(void);
 static void GL_BINDING_CALL Mock_glSampleCoverage(GLclampf value,
                                                   GLboolean invert);
 static void GL_BINDING_CALL
 Mock_glSamplerParameterIivRobustANGLE(GLuint sampler,
                                       GLenum pname,
                                       GLsizei bufSize,
                                       const GLint* param);
 static void GL_BINDING_CALL
 Mock_glSamplerParameterIuivRobustANGLE(GLuint sampler,
@@ skipping 400 matching lines @@
                                                        GLboolean normalized,
                                                        GLsizei stride,
                                                        const void* ptr);
 static void GL_BINDING_CALL Mock_glViewport(GLint x,
                                             GLint y,
                                             GLsizei width,
                                             GLsizei height);
 static GLenum GL_BINDING_CALL Mock_glWaitSync(GLsync sync,
                                               GLbitfield flags,
                                               GLuint64 timeout);