Add glTransformFeedbackVaryings to GPU command buffer.

gpu/command_buffer/client/gles2_interface_stub_autogen.h

 // Copyright 2014 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
 // gpu/command_buffer/build_gles2_cmd_buffer.py
 // It's formatted by clang-format using chromium coding style:
 //    clang-format -i -style=chromium filename
 // DO NOT EDIT!
 
@@ skipping 349 matching lines @@
                    GLint level,
                    GLint xoffset,
                    GLint yoffset,
                    GLint zoffset,
                    GLsizei width,
                    GLsizei height,
                    GLsizei depth,
                    GLenum format,
                    GLenum type,
                    const void* pixels) override;
+void TransformFeedbackVaryings(GLuint program,
+                               GLsizei count,
+                               const char* const* varyings,
+                               GLenum buffermode) override;
 void Uniform1f(GLint location, GLfloat x) override;
 void Uniform1fv(GLint location, GLsizei count, const GLfloat* v) override;
 void Uniform1i(GLint location, GLint x) override;
 void Uniform1iv(GLint location, GLsizei count, const GLint* v) override;
 void Uniform1ui(GLint location, GLuint x) override;
 void Uniform1uiv(GLint location, GLsizei count, const GLuint* v) override;
 void Uniform2f(GLint location, GLfloat x, GLfloat y) override;
 void Uniform2fv(GLint location, GLsizei count, const GLfloat* v) override;
 void Uniform2i(GLint location, GLint x, GLint y) override;
 void Uniform2iv(GLint location, GLsizei count, const GLint* v) override;
@@ skipping 268 matching lines @@
                                   GLint bounds_height,
                                   GLfloat uv_x,
                                   GLfloat uv_y,
                                   GLfloat uv_width,
                                   GLfloat uv_height) override;
 void SwapInterval(GLint interval) override;
 void MatrixLoadfCHROMIUM(GLenum matrixMode, const GLfloat* m) override;
 void MatrixLoadIdentityCHROMIUM(GLenum matrixMode) override;
 void BlendBarrierKHR() override;
 #endif  // GPU_COMMAND_BUFFER_CLIENT_GLES2_INTERFACE_STUB_AUTOGEN_H_