Implement a proxy for Pepper FileIO.

ppapi/c/ppb_file_io.h

Index: ppapi/c/ppb_file_io.h
diff --git a/ppapi/c/ppb_file_io.h b/ppapi/c/ppb_file_io.h
index 333984ba66ad3dfdd5d4f7f1d63cdb46f09fdd7f..5c7040298a55aa5376ff0dfcea1f0ccb69cf6d93 100644
--- a/ppapi/c/ppb_file_io.h
+++ b/ppapi/c/ppb_file_io.h
@@ -3,7 +3,7 @@
  * found in the LICENSE file.
  */
 
-/* From ppb_file_io.idl modified Mon Aug 29 10:11:34 2011. */
+/* From ppb_file_io.idl modified Tue Nov 29 11:02:24 2011. */
 
 #ifndef PPAPI_C_PPB_FILE_IO_H_
 #define PPAPI_C_PPB_FILE_IO_H_
@@ -117,8 +117,9 @@ struct PPB_FileIO {
                   int32_t open_flags,
                   struct PP_CompletionCallback callback);
   /**
-   * Query() queries info about the file opened by this FileIO object. This
-   * function will fail if the FileIO object has not been opened.
+   * Query() queries info about the file opened by this FileIO object. The
+   * FileIO object must be opened, and there must be no other operations
+   * pending.
    *
    * @param[in] file_io A <code>PP_Resource</code> corresponding to a
    * FileIO.
@@ -128,6 +129,8 @@ struct PPB_FileIO {
    * completion of Query().
    *
    * @return An int32_t containing an error code from <code>pp_errors.h</code>.
+   * PP_ERROR_FAILED will be returned if the file isn't opened, and
+   * PP_ERROR_INPROGRESS will be returned if there is another operation pending.
    */
   int32_t (*Query)(PP_Resource file_io,
                    struct PP_FileInfo* info,
@@ -166,7 +169,8 @@ struct PPB_FileIO {
    * @return An The number of bytes read an error code from
    * <code>pp_errors.h</code>. If the return value is 0, then end-of-file was
    * reached. It is valid to call Read() multiple times with a completion
-   * callback to queue up parallel reads from the file at different offsets.
+   * callback to queue up parallel reads from the file at different offsets,
+   * but pending reads can not be interleaved with other operations.
    */
   int32_t (*Read)(PP_Resource file_io,
                   int64_t offset,
@@ -189,7 +193,8 @@ struct PPB_FileIO {
    * @return An The number of bytes written or an error code from
    * <code>pp_errors.h</code>. If the return value is 0, then end-of-file was
    * reached. It is valid to call Write() multiple times with a completion
-   * callback to queue up parallel writes to the file at different offsets.
+   * callback to queue up parallel writes to the file at different offsets, but
+   * pending writes can not be interleaved with other operations.
    */
   int32_t (*Write)(PP_Resource file_io,
                    int64_t offset,