Widen one suppression to match linux bot, add one new suppression for mac....

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 # running overnight and removing outdated bugs/suppressions.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 535 matching lines @@
    fun:+[NSObject allocWithZone:]
    fun:-[NSCustomObject nibInstantiate]
    fun:-[NSIBObjectData instantiateObject:]
    fun:-[NSIBObjectData nibInstantiateWithOwner:topLevelObjects:]
    fun:loadNib
    fun:+[NSBundle(NSNibLoading) _loadNibFile:nameTable:withZone:ownerBundle:]
    fun:+[NSBundle(NSNibLoading) loadNibFile:externalNameTable:withZone:]
    fun:+[NSBundle(NSNibLoading) loadNibNamed:owner:]
    fun:_ZN8Platform29WillInitializeMainMessageLoopERK18MainFunctionParams
 }
+{
+   bug_20541
+   Memcheck:Leak
+   fun:malloc_zone_malloc
+   fun:_CFRuntimeCreateInstance
+   fun:CFRunLoopSourceCreate
+   fun:CFMachPortCreateRunLoopSource
+   ...
+   fun:SecKeychainAddCallback
+   ...
+   fun:SecTrustSettingsEvaluateCert
+   ...
+   fun:SecTrustEvaluate
+   fun:_ZNK3net15X509Certificate6VerifyERKSsiPNS_16CertVerifyResultE
+}