Change PPB_VideoWriter Open function to return stream_id as out param.

ppapi/c/ppb_video_writer.h

 /* Copyright (c) 2013 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.
  */
 
-/* From ppb_video_writer.idl modified Thu Apr  4 13:47:32 2013. */
+/* From ppb_video_writer.idl modified Fri Apr  5 15:46:57 2013. */
 
 #ifndef PPAPI_C_PPB_VIDEO_WRITER_H_
 #define PPAPI_C_PPB_VIDEO_WRITER_H_
 
 #include "ppapi/c/pp_bool.h"
 #include "ppapi/c/pp_completion_callback.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_macros.h"
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/c/pp_stdint.h"
@@ skipping 38 matching lines @@
    *
    * @return A <code>PP_Bool</code> with <code>PP_TRUE</code> if the given
    * resource is a video writer or <code>PP_FALSE</code> otherwise.
    */
   PP_Bool (*IsVideoWriter)(PP_Resource resource);
   /**
    * Opens a video stream with the given id for writing.
    *
    * @param[in] writer A <code>PP_Resource</code> corresponding to a video
    * writer resource.
-   * @param[in] stream_id A <code>PP_Var</code> holding a string uniquely
-   * identifying the stream. This string is application defined.
+   * @param[out] stream_id A <code>PP_Var</code> holding a string uniquely
+   * identifying the stream. This string is generated by the host.
    * @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
    * completion of Open().
    *
    * @return An int32_t containing an error code from <code>pp_errors.h</code>.
    * Returns PP_ERROR_BADRESOURCE if writer isn't a valid video writer.
    * Returns PP_ERROR_INPROGRESS if the writer has already opened a stream.
    */
   int32_t (*Open)(PP_Resource writer,
-                  struct PP_Var stream_id,
+                  struct PP_Var* stream_id,
                   struct PP_CompletionCallback callback);
   /**
    * Puts a frame of video to the writer's open stream.
    *
    * After this call, you should take care to release your references to the
    * image embedded in the video frame. If you paint to the image after
    * PutFrame(), there is the possibility of artifacts because the browser may
    * still be copying the frame to the stream.
    *
    * @param[in] writer A <code>PP_Resource</code> corresponding to a video
@@ skipping 16 matching lines @@
   void (*Close)(PP_Resource writer);
 };
 
 typedef struct PPB_VideoWriter_0_1 PPB_VideoWriter;
 /**
  * @}
  */
 
 #endif  /* PPAPI_C_PPB_VIDEO_WRITER_H_ */