Suppress a new leak in net::DnsReloadTimer::Expired().

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 # running overnight and removing outdated bugs/suppressions.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 3572 matching lines @@
    fun:_ZN15SyncSetupWizard*EP18ProfileSyncService
    fun:_ZN18ProfileSyncService*
    fun:_ZN22ProfileSync*
    ...
    fun:*GetProfileSyncServiceEv
    fun:_ZN7Profile16IsSyncAccessibleEv
    fun:_ZN7Browser31UpdateCommandsForFullscreenModeEb
    fun:_ZN7Browser16InitCommandStateEv
    fun:_ZN7Browser*ENS_4TypeEP7Profile
 }
+{
+   bug_50579
+   Memcheck:Leak
+   fun:_Znw*
+   fun:_ZN3net14DnsReloadTimer7ExpiredEv
+   fun:_ZN3net24DnsReloadTimerHasExpiredEv
+   fun:_ZN3net22SystemHostResolverProcERKSsNS_13AddressFamilyEiPNS_11AddressListEPi
+   fun:_ZN3net15ResolveAddrInfoEPNS_16HostResolverProcERKSsNS_13AddressFamilyEiPNS_11AddressListEPi
+   fun:_ZN3net16HostResolverImpl3Job8DoLookupEv
+   fun:_Z16DispatchToMethodIN3net16HostResolverImpl3JobEMS2_FvvEEvPT_T0_RK6Tuple0
+   fun:_ZN14RunnableMethodIN3net16HostResolverImpl3JobEMS2_FvvE6Tuple0E3RunEv
+}