Suppress uninitialized read in file_util::FileEnumerator::Next()

tools/valgrind/memcheck/suppressions_mac.txt

 # There are three kinds of suppressions in this file:
 # 1. Third party stuff we have no control over.
 #
 # 2. Intentional unit test errors, stuff that is somehow a false positive
 # in our own code, or stuff that is so trivial it's not worth fixing.
 #
 # 3. Suppressions for real chromium bugs that are not yet fixed.
 # These should all be in chromium's bug tracking system.
 # Periodically we should sweep this file and the bug tracker clean by
 # running overnight and removing outdated bugs/suppressions.
@@ skipping 2363 matching lines @@
    Memcheck:Param
    write(buf)
    fun:write$UNIX2003
 }
 {
    bug_178424d
    Memcheck:Param
    read(buf)
    fun:read$UNIX2003
 }
+{
+   bug_231969
+   Memcheck:Uninitialized
+   fun:rangematch
+   fun:fnmatch1
+   fun:fnmatch1
+   fun:fnmatch$UNIX2003
+   fun:_ZN9file_util14FileEnumerator4NextEv
+   fun:_ZN10disk_cache11SimpleIndex15RestoreFromDiskERKN4base8FilePathE
+   fun:_ZN10disk_cache11SimpleIndex12LoadFromDiskERKN4base8FilePathERK13scoped_refptrINS1_10TaskRunnerEERKNS1_8CallbackIFv10scoped_ptrIN9__gnu_cxx8hash_mapIyNS_13EntryMetadataENSC_4hashIyEESt8equal_toIyESaISE_EEENS1_14DefaultDeleterISK_EEEEEE
+}