Suppress data race in UI (bug 51890) and remove a suppression for a race fixe...

tools/valgrind/tsan/suppressions.txt

 ############################
 # Chromium
 
 {
   bug_23433
   ThreadSanitizer:Race
   fun:*logging*SetMinLogLevel*
 }
 
 {
   bug_24419
   ThreadSanitizer:Race
   fun:*BrowserProcessImpl*nspector*iles*
 }
 
 {
-  bug_25915
-  ThreadSanitizer:Race
-  fun:*browser_sync*BookmarkModelWorker*
-}
-
-{
   bug_37496
   ThreadSanitizer:Race
   ...
   fun:*browser_sync*SyncShareIntercept*Observe*
 }
 
 {
   bug_46642a
   ThreadSanitizer:Race
   fun:*media*PipelineImpl*InitializeTask*
 }
 
 {
   bug_46642b
   ThreadSanitizer:Race
   fun:*media*PipelineImpl*GetCurrentTime*
 }
 
+{
+  bug_51890a
+  ThreadSanitizer:Race
+  ...
+  fun:history::TopSites::GenerateCanonicalURLs*
+  fun:history::TopSites::StoreMostVisited*
+}
+
+{
+  bug_51890b
+  ThreadSanitizer:Race
+  ...
+  fun:history::TopSites::SetPageThumbnail*
+  fun:TabContents::UpdateThumbnail*
+}
+
 ############################
 # Real races in third_party
 {
   bug_23244 (libevent)
   ThreadSanitizer:Race
   fun:event_*
   fun:event_*
 }
 
 {
@@ skipping 236 matching lines @@
   ThreadSanitizer:Race
   ...
   fun:gethostbyname2_r*
 }
 
 {
   Benign race in nss (PR_EnterMonitor)
   ThreadSanitizer:Race
   fun:PR_EnterMonitor
 }