More memory suppressions:

tools/valgrind/memcheck/suppressions.txt

 # There are four 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 # running overnight and removing outdated bugs/suppressions.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 7276 matching lines @@
 }
 {
    bug_252241_b
    Memcheck:Leak
    fun:_Znw*
    fun:_ZN7content19ContentMainDelegate26CreateContentUtilityClientEv
    fun:_ZN7content24ContentClientInitializer3SetERKSsPNS_19ContentMainDelegateE
    fun:_ZN7content21ContentMainRunnerImpl10InitializeEiPPKcPNS_19ContentMainDelegateE
    fun:_ZN7content11ContentMainEiPPKcPNS_19ContentMainDelegateE
 }
+{
+   bug_252615
+   Memcheck:Leak
+   fun:malloc
+   fun:XGetWindowProperty
+   fun:XFetchName
+   fun:_ZN3ash4test12_GLOBAL__N_114GetXWindowNameEPN4aura10RootWindowE
+   fun:_ZN3ash4test50DisplayControllerTest_XWidowNameForRootWindow_Test8TestBodyEv
+}
+{
+   bug_252641
+   Memcheck:Uninitialized
+   fun:pthread_rwlock_init$UNIX2003
+   fun:_ZN3re25MutexC2Ev
+   fun:_ZN3re25MutexC1Ev
+   ...
+   fun:_ZN11leveldb_env19ParseMethodAndErrorEPKcPNS_8MethodIDEPi
+   fun:_ZN7contentL21HistogramLevelDBErrorERKSsRKN7leveldb6StatusE
+   fun:_ZN7content15LevelDBDatabase4OpenERKN4base8FilePathEPKNS_17LevelDBComparatorEPb
+   fun:_ZN7content12_GLOBAL__N_139LevelDBDatabaseTest_CorruptionTest_Test8TestBodyEv
+}
+