Add new PPB_OPENGLES2_DRAWBUFFERS_DEV_INTERFACE_1_0 pepper interface.

ppapi/lib/gl/gles2/gles2.c

 // Copyright (c) 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 1037 matching lines @@
     ext->DrawElementsInstancedANGLE(
         glGetCurrentContextPPAPI(), mode, count, type, indices, primcount);
 }
 
 void GL_APIENTRY glVertexAttribDivisorANGLE(GLuint index, GLuint divisor) {
   const struct PPB_OpenGLES2InstancedArrays* ext =
       glGetInstancedArraysInterfacePPAPI();
   if (ext)
     ext->VertexAttribDivisorANGLE(glGetCurrentContextPPAPI(), index, divisor);
 }
+void GL_APIENTRY glDrawBuffersEXT(GLsizei count, const GLenum* bufs) {
+  const struct PPB_OpenGLES2DrawBuffers_Dev* ext =
+      glGetDrawBuffersInterfacePPAPI();
+  if (ext)
+    ext->DrawBuffersEXT(glGetCurrentContextPPAPI(), count, bufs);
+}
+