Add variants for two existing suppressions.

tools/valgrind/memcheck/suppressions.txt

 # There are three kinds of suppressions in this file.
 # 1. third party stuff we have no control over
 #
 # 2. intentional unit test errors, or 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 (but a few aren't yet).
 # Periodically we should sweep this file and the bug tracker clean by
 # running overnight and removing outdated bugs/suppressions.
@@ skipping 848 matching lines @@
 {
    # ditto, but tweak to match the chromeos's stack.
    bug_16089d
    Memcheck:Leak
    fun:*
    ...
    fun:_ZN4base22LinuxDynamicThreadPool8PostTaskEP4Task
    ...
    fun:_ZN3net16HostResolverImpl3Job5StartEv
 }
+
+{
+   # ditto, but for IPv6 support (?)
+   bug_16089e
+   Memcheck:Leak
+   fun:*
+   ...
+   fun:_ZN4base22LinuxDynamicThreadPool8PostTaskEP4Task
+   ...
+   fun:_ZN3net16HostResolverImpl16ProbeIPv6SupportEv
+}
 {
    # very common in ui tests
    bug_16091
    Memcheck:Leak
    ...
    fun:_ZN11MessageLoop22AddDestructionObserverEPNS_19DestructionObserverE
    ...
    fun:_ZN3IPC11SyncChannel11SyncContext15OnChannelOpenedEv
 }
 {
@@ skipping 202 matching lines @@
 {
    bug_19371
    Memcheck:Leak
    fun:_Znw*
    ...
    fun:_ZN4base13WaitableEvent7EnqueueEPNS0_6WaiterE
    fun:_ZN4base13WaitableEvent9TimedWaitERKNS_9TimeDeltaE
    fun:_ZN4base13WaitableEvent4WaitEv
    fun:_ZN4base18MessagePumpDefault3RunEPNS_11MessagePump8DelegateE
 }
+
+{
+   # slight variant of the above
+   bug_19371a
+   Memcheck:Leak
+   fun:_Znw*
+   ...
+   fun:_ZN4base13WaitableEvent7EnqueueEPNS0_6WaiterE
+   fun:_ZN4base13WaitableEvent9TimedWaitERKNS_9TimeDeltaE
+   fun:_ZN4base18MessagePumpDefault3RunEPNS_11MessagePump8DelegateE
+}
 {
    bug_19377
    Memcheck:Leak
    fun:calloc
    ...
    fun:event_base_new
    fun:_ZN4base19MessagePumpLibeventC1Ev
    fun:_ZN11MessageLoopC1ENS_4TypeE
    fun:_ZN4base6Thread10ThreadMainEv
 }
@@ skipping 1971 matching lines @@
 }
 
 {
    bug_46144
    Memcheck:Leak
    fun:malloc
    fun:_ZN3WTF10fastMallocEj
    fun:_ZN3WTF13FastAllocBasenwEj
    fun:_ZN3WTF20ThreadIdentifierData10initializeEj
 }