Change mojo enums to be scoped enums in the generated C++ bindings.

skia/public/interfaces/bitmap.mojom

 // Copyright 2015 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 contains structures used to represent SkBitmaps in Mojo.
 module skia;
 
 // Mirror of SkColorType.
 enum ColorType {
   UNKNOWN,
   ALPHA_8,
   RGB_565,
   ARGB_4444,
   RGBA_8888,
   BGRA_8888,
   INDEX_8,
   GRAY_8,
 };
 
 // Mirror of SkAlphaType.
 enum AlphaType {
   UNKNOWN,
-  OPAQUE,
+  ALPHA_TYPE_OPAQUE,
   PREMUL,
   UNPREMUL,
 };
 
 // Mirror of SkColorProfileType.
 enum ColorProfileType {
   LINEAR,
   SRGB,
 };
 
 struct Bitmap {
   ColorType color_type;
   AlphaType alpha_type;
   ColorProfileType profile_type;
 
   uint32 width;
   uint32 height;
 
   array<uint8> pixel_data;
 };