Switch to standard integer types in sync/.

sync/internal_api/attachments/on_disk_attachment_store.cc

Index: sync/internal_api/attachments/on_disk_attachment_store.cc
diff --git a/sync/internal_api/attachments/on_disk_attachment_store.cc b/sync/internal_api/attachments/on_disk_attachment_store.cc
index a9bab4783dd2bcc49150d9a03d343d1ef89b37d3..c579c4598d83ac29957b61070c6342193f660991 100644
--- a/sync/internal_api/attachments/on_disk_attachment_store.cc
+++ b/sync/internal_api/attachments/on_disk_attachment_store.cc
@@ -4,6 +4,8 @@
 
 #include "sync/internal_api/public/attachments/on_disk_attachment_store.h"
 
+#include <stdint.h>
+
 #include <string>
 
 #include "base/bind.h"
@@ -34,7 +36,7 @@ const char kMetadataPrefix[] = "metadata-";
 
 const char kDatabaseMetadataKey[] = "database-metadata";
 
-const int32 kCurrentSchemaVersion = 1;
+const int32_t kCurrentSchemaVersion = 1;
 
 const base::FilePath::CharType kLeveldbDirectory[] =
     FILE_PATH_LITERAL("leveldb");