Convert to new enter method

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 709af4379598863ca435eb13cedb2192c3de43ec..c291ec8c9869171687990393b13dc9dfee2f0669 100644
--- a/ppapi/thunk/ppb_file_io_trusted_thunk.cc
+++ b/ppapi/thunk/ppb_file_io_trusted_thunk.cc
@@ -5,7 +5,6 @@
 #include "ppapi/c/pp_completion_callback.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/c/trusted/ppb_file_io_trusted.h"
-#include "ppapi/thunk/common.h"
 #include "ppapi/thunk/enter.h"
 #include "ppapi/thunk/thunk.h"
 #include "ppapi/thunk/ppb_file_io_api.h"
@@ -16,32 +15,33 @@ namespace thunk {
 
 namespace {
 
+typedef EnterResource<PPB_FileIO_API> EnterFileIO;
+
 int32_t GetOSFileDescriptor(PP_Resource file_io) {
-  EnterResource<PPB_FileIO_API> enter(file_io, true);
+  EnterFileIO enter(file_io, true);
   if (enter.failed())
-    return PP_ERROR_BADRESOURCE;
-  return enter.object()->GetOSFileDescriptor();
+    return enter.retval();
+  return enter.SetResult(enter.object()->GetOSFileDescriptor());
 }
 
 int32_t WillWrite(PP_Resource file_io,
                   int64_t offset,
                   int32_t bytes_to_write,
                   PP_CompletionCallback callback) {
-  EnterResource<PPB_FileIO_API> enter(file_io, true);
+  EnterFileIO enter(file_io, callback, true);
   if (enter.failed())
-    return MayForceCallback(callback, PP_ERROR_BADRESOURCE);
-  int32_t result =  enter.object()->WillWrite(offset, bytes_to_write, callback);
-  return MayForceCallback(callback, result);
+    return enter.retval();
+  return enter.SetResult(enter.object()->WillWrite(offset, bytes_to_write,
+                                                   callback));
 }
 
 int32_t WillSetLength(PP_Resource file_io,
                       int64_t length,
                       PP_CompletionCallback callback) {
-  EnterResource<PPB_FileIO_API> enter(file_io, true);
+  EnterFileIO enter(file_io, callback, true);
   if (enter.failed())
-    return MayForceCallback(callback, PP_ERROR_BADRESOURCE);
-  int32_t result = enter.object()->WillSetLength(length, callback);
-  return MayForceCallback(callback, result);
+    return enter.retval();
+  return enter.SetResult(enter.object()->WillSetLength(length, callback));
 }
 
 const PPB_FileIOTrusted g_ppb_file_io_trusted_thunk = {