Add a second unsafe ES3 API in command buffer.

gpu/command_buffer/client/gles2_c_lib_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 98 matching lines @@
                                   GLint xoffset,
                                   GLint yoffset,
                                   GLsizei width,
                                   GLsizei height,
                                   GLenum format,
                                   GLsizei imageSize,
                                   const void* data) {
   gles2::GetGLContext()->CompressedTexSubImage2D(
       target, level, xoffset, yoffset, width, height, format, imageSize, data);
 }
+void GLES2CopyBufferSubData(GLenum readtarget,
+                            GLenum writetarget,
+                            GLintptr readoffset,
+                            GLintptr writeoffset,
+                            GLsizeiptr size) {
+  gles2::GetGLContext()->CopyBufferSubData(readtarget, writetarget, readoffset,
+                                           writeoffset, size);
+}
 void GLES2CopyTexImage2D(GLenum target,
                          GLint level,
                          GLenum internalformat,
                          GLint x,
                          GLint y,
                          GLsizei width,
                          GLsizei height,
                          GLint border) {
   gles2::GetGLContext()->CopyTexImage2D(target, level, internalformat, x, y,
                                         width, height, border);
@@ skipping 926 matching lines @@
     },
     {
      "glCompressedTexImage2D",
      reinterpret_cast<GLES2FunctionPointer>(glCompressedTexImage2D),
     },
     {
      "glCompressedTexSubImage2D",
      reinterpret_cast<GLES2FunctionPointer>(glCompressedTexSubImage2D),
     },
     {
+     "glCopyBufferSubData",
+     reinterpret_cast<GLES2FunctionPointer>(glCopyBufferSubData),
+    },
+    {
      "glCopyTexImage2D",
      reinterpret_cast<GLES2FunctionPointer>(glCopyTexImage2D),
     },
     {
      "glCopyTexSubImage2D",
      reinterpret_cast<GLES2FunctionPointer>(glCopyTexSubImage2D),
     },
     {
      "glCreateProgram",
      reinterpret_cast<GLES2FunctionPointer>(glCreateProgram),
@@ skipping 781 matching lines @@
      reinterpret_cast<GLES2FunctionPointer>(glBlendBarrierKHR),
     },
     {
      NULL,
      NULL,
     },
 };
 
 }  // namespace gles2
 #endif  // GPU_COMMAND_BUFFER_CLIENT_GLES2_C_LIB_AUTOGEN_H_