Leaks found in UI tests including ResourceMessageFilter::OnMessageReceived

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 # running overnight and removing outdated bugs/suppressions.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 3898 matching lines @@
    Memcheck:Leak
    fun:_Znw*
    fun:_ZN41PrefValueStoreTest_TestPolicyRefresh_Test8TestBodyEv
 }
 {
    bug_51176_c
    Memcheck:Leak
    fun:_Znw*
    fun:_ZN56PrefValueStoreTest_TestRefreshPolicyPrefsCompletion_Test8TestBodyEv
 }
+{
+   bug_51218
+   Memcheck:Leak
+   fun:_Znw*
+   fun:_ZN3IPC11SyncMessage13GenerateReplyEPKNS_7MessageE
+   fun:_ZN3IPC16MessageWithReplyI6Tuple3I4GURLSsSsE6Tuple2IRNS_13ChannelHandleER13WebPluginInfoEE18DispatchDelayReplyI21ResourceMessageFilterMSC_FvRKS2_RKSsSG_PNS_7MessageEEEEbPKSH_PT_T0_
+   fun:_ZN21ResourceMessageFilter17OnMessageReceivedERKN3IPC7MessageE
+   fun:_ZN3IPC12ChannelProxy7Context10TryFiltersERKNS_7MessageE
+   fun:_ZN3IPC11SyncChannel11SyncContext17OnMessageReceivedERKNS_7MessageE
+   fun:_ZN3IPC7Channel11ChannelImpl23ProcessIncomingMessagesEv
+   fun:_ZN3IPC7Channel11ChannelImpl28OnFileCanReadWithoutBlockingEi
+}