PPAPI: Make blocking completion callbacks work.

ppapi/thunk/ppb_file_io_trusted_thunk.cc

Index: ppapi/thunk/ppb_file_io_trusted_thunk.cc
diff --git a/ppapi/thunk/ppb_file_io_trusted_thunk.cc b/ppapi/thunk/ppb_file_io_trusted_thunk.cc
index c291ec8c9869171687990393b13dc9dfee2f0669..3336026e8e487a0438990a4f36daeecfce7cb635 100644
--- a/ppapi/thunk/ppb_file_io_trusted_thunk.cc
+++ b/ppapi/thunk/ppb_file_io_trusted_thunk.cc
@@ -5,6 +5,7 @@
 #include "ppapi/c/pp_completion_callback.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/c/trusted/ppb_file_io_trusted.h"
+#include "ppapi/shared_impl/tracked_callback.h"
 #include "ppapi/thunk/enter.h"
 #include "ppapi/thunk/thunk.h"
 #include "ppapi/thunk/ppb_file_io_api.h"
@@ -21,7 +22,7 @@ int32_t GetOSFileDescriptor(PP_Resource file_io) {
   EnterFileIO enter(file_io, true);
   if (enter.failed())
     return enter.retval();
-  return enter.SetResult(enter.object()->GetOSFileDescriptor());
+  return enter.object()->GetOSFileDescriptor();
 }
 
 int32_t WillWrite(PP_Resource file_io,
@@ -32,7 +33,7 @@ int32_t WillWrite(PP_Resource file_io,
   if (enter.failed())
     return enter.retval();
   return enter.SetResult(enter.object()->WillWrite(offset, bytes_to_write,
-                                                   callback));
+                                                   enter.callback()));
 }
 
 int32_t WillSetLength(PP_Resource file_io,
@@ -41,7 +42,8 @@ int32_t WillSetLength(PP_Resource file_io,
   EnterFileIO enter(file_io, callback, true);
   if (enter.failed())
     return enter.retval();
-  return enter.SetResult(enter.object()->WillSetLength(length, callback));
+  return enter.SetResult(enter.object()->WillSetLength(length,
+                                                       enter.callback()));
 }
 
 const PPB_FileIOTrusted g_ppb_file_io_trusted_thunk = {