Suppress a leak in invalidation::NewPermanentCallback (issue 88438)

tools/heapcheck/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 # running overnight and removing outdated bugs/suppressions.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 1525 matching lines @@
    Heapcheck:Leak
    ...
    fun:content_settings::PrefProviderTest_MigrateSinglePatternSettings_Test::TestBody
 }
 {
    bug_88212
    Heapcheck:Leak
    fun:TestingProfile::CreateRequestContext
    fun:ProfileSyncService*Test::SetUp
 }
-
+{
+   bug_88438
+   Heapcheck:Leak
+   fun:invalidation::NewPermanentCallback
+   fun:invalidation::InvalidationClientImpl::ScheduleStartAfterReadingStateBlob
+   fun:invalidation::InvalidationClientImpl::Start
+   fun:sync_notifier::ChromeInvalidationClient::Start
+}