PPAPI: Make blocking completion callbacks work.

webkit/plugins/ppapi/ppb_directory_reader_impl.cc

Index: webkit/plugins/ppapi/ppb_directory_reader_impl.cc
diff --git a/webkit/plugins/ppapi/ppb_directory_reader_impl.cc b/webkit/plugins/ppapi/ppb_directory_reader_impl.cc
index 2f381217fdd365c490f6e7e77b7f65c519c173af..d93da9282617bc1fd9b2f8b2e414c853c375a8ae 100644
--- a/webkit/plugins/ppapi/ppb_directory_reader_impl.cc
+++ b/webkit/plugins/ppapi/ppb_directory_reader_impl.cc
@@ -22,6 +22,7 @@
 #include "webkit/plugins/ppapi/ppb_file_system_impl.h"
 #include "webkit/plugins/ppapi/resource_helper.h"
 
+using ppapi::ApiCallbackType;
 using ::ppapi::PpapiGlobals;
 using ::ppapi::thunk::EnterResourceNoLock;
 using ::ppapi::thunk::PPB_DirectoryReader_API;
@@ -78,11 +79,8 @@ PPB_DirectoryReader_API* PPB_DirectoryReader_Impl::AsPPB_DirectoryReader_API() {
   return this;
 }
 
-int32_t PPB_DirectoryReader_Impl::GetNextEntry(
-    PP_DirectoryEntry_Dev* entry,
-    PP_CompletionCallback callback) {
-  if (!callback.func)
-    return PP_ERROR_BLOCKS_MAIN_THREAD;
+int32_t PPB_DirectoryReader_Impl::GetNextEntry(PP_DirectoryEntry_Dev* entry,
+                                               ApiCallbackType callback) {
   if (directory_ref_->GetFileSystemType() == PP_FILESYSTEMTYPE_EXTERNAL)
     return PP_ERROR_FAILED;