Clean up Pepper ImageData resource class.

ppapi/shared_impl/ppb_image_data_shared.h

 // Copyright (c) 2011 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.
 
 #ifndef PPAPI_SHARED_IMPL_PPB_IMAGE_DATA_SHARED_H_
 #define PPAPI_SHARED_IMPL_PPB_IMAGE_DATA_SHARED_H_
 
 #include "ppapi/c/pp_bool.h"
 #include "ppapi/c/ppb_image_data.h"
 #include "ppapi/shared_impl/ppapi_shared_export.h"
 
 namespace ppapi {
 
 // Contains the implementation of some simple image data functions that are
 // shared between the proxy and Chrome's implementation. Since these functions
 // are just lists of what we support, it's much easier to just have the same
 // code run in the plugin process than to proxy it.
 //
 // It's possible the implementation will get more complex. In this case, it's
 // probably best to have some kind of "configuration" message that the renderer
 // sends to the plugin process on startup that contains all of these kind of
 // settings.
 class PPAPI_SHARED_EXPORT PPB_ImageData_Shared {
  public:
+  enum ImageDataType {
+    // An ImageData backed by a PlatformCanvas. You must create this type if
+    // you intend the ImageData to be usable in platform-specific APIs (like
+    // font rendering or rendering widgets like scrollbars). This type is not
+    // available in untrusted (NaCl) plugins.
+    PLATFORM,
+    // An ImageData that doesn't need access to the platform-specific canvas.
+    // This is backed by a simple shared memory buffer. This is the only type
+    // of ImageData that can be used by untrusted (NaCl) plugins.
+    SIMPLE
+  };
+
   static PP_ImageDataFormat GetNativeImageDataFormat();
   static PP_Bool IsImageDataFormatSupported(PP_ImageDataFormat format);
   static PP_Bool IsImageDataDescValid(const PP_ImageDataDesc& desc);
 };
 
 }  // namespace ppapi
 
 #endif  // PPAPI_SHARED_IMPL_PPB_IMAGE_DATA_SHARED_H_