ResourceHandleMac uses shouldUseCredentialStorage internally. It's not a real problem for NetworkProcess, as it doesn't have to do IPC to reply, although it of course breaks the model somewhat.
Created attachment 196020 [details]
Attachment 196020 [details] did not pass style-queue:
Failed to run "['Tools/Scripts/check-webkit-style', '--diff-files', u'Source/WebCore/ChangeLog', u'Source/WebCore/platform/network/mac/ResourceHandleMac.mm', u'Source/WebKit2/ChangeLog', u'Source/WebKit2/NetworkProcess/NetworkResourceLoader.cpp', u'Source/WebKit2/NetworkProcess/NetworkResourceLoader.h']" exit_code: 1
Source/WebKit2/ChangeLog:1: ChangeLog entry has no bug number [changelog/bugnumber] 
Total errors found: 1 in 5 files
If any of these errors are false positives, please file a bug against check-webkit-style.