Remove the last Histogram suppression

tools/valgrind/tsan/suppressions.txt

 # There are a few 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 # running overnight and removing outdated bugs/suppressions.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 335 matching lines @@
 }
 
 ############################
 # 2.2 Benign races in Chromium
 {
   bug_61179 [benign race on tracked_objects::Births]
   ThreadSanitizer:Race
   fun:tracked_objects::Births::*Birth*
 }
 
-{
-   benign race on Histogram::Add - TO BE REMOVED SOON
-   ThreadSanitizer:Race
-   ...
-   fun:base::SampleVector::Accumulate
-   fun:base::Histogram::Add
-}
-
 # 3. Suppressions for real chromium bugs that are not yet fixed.
 ############################
 # Real races in Chromium
 {
   bug_24419
   ThreadSanitizer:Race
   fun:*BrowserProcessImpl*nspector*iles*
 }
 
 {
@@ skipping 577 matching lines @@
   fun:*
   fun:base::internal::RunnableAdapter::Run
 }
 {
   bug_172306
   ThreadSanitizer:Race
   fun:ThreadWatcher::OnPongMessage
   fun:CustomThreadWatcher::OnPongMessage
   fun:base::internal::RunnableAdapter::Run
 }