media: Add MojoDecoderBuffer{Reader|Writer}

media/mojo/common/BUILD.gn

 # 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.
 
 import("//testing/test.gni")
 
 # Target naming conventions:
 # - unittests: Unit tests for a particular class/file.
 
 source_set("common") {
   sources = [
     "media_type_converters.cc",
     "media_type_converters.h",
+    "mojo_decoder_buffer_converter.cc",
+    "mojo_decoder_buffer_converter.h",
     "mojo_shared_buffer_video_frame.cc",
     "mojo_shared_buffer_video_frame.h",
     "mojo_type_trait.h",
   ]
 
   deps = [
     "//base",
     "//media",
     "//media/mojo/interfaces",
     "//mojo/common",
     "//mojo/public/cpp/bindings",
     "//mojo/public/cpp/system",
     "//ui/gfx/geometry",
     "//ui/gfx/geometry/mojo",
   ]
 }