The 32- and 64-bit plists are virtually identical. They can share a single plist and rely on build setting expansion to fill in the differences.
Created attachment 189415 [details]
Created attachment 189417 [details]
Attachment 189417 [details] did not pass style-queue:
Failed to run "['Tools/Scripts/check-webkit-style', '--diff-files', u'Source/WebKit2/ChangeLog', u'Source/WebKit2/Configurations/PluginService.32.xcconfig', u'Source/WebKit2/Configurations/PluginService.64.xcconfig', u'Source/WebKit2/PluginProcess/EntryPoint/mac/XPCService/PluginService.32-64.Info.plist', u'Source/WebKit2/PluginProcess/EntryPoint/mac/XPCService/PluginService.32/Info.plist', u'Source/WebKit2/PluginProcess/EntryPoint/mac/XPCService/PluginService.64/Info.plist']" exit_code: 1
Source/WebKit2/ChangeLog:1: ChangeLog entry has no bug number [changelog/bugnumber] 
Total errors found: 1 in 4 files
If any of these errors are false positives, please file a bug against check-webkit-style.
Landed in r143543.