Make URLRequestThrottlerEntryInterface inherit RefCountedThreadSafe,

tools/valgrind/tsan/suppressions.txt

 ############################
 # Chromium
 
 {
   bug_23433
   ThreadSanitizer:Race
   fun:*logging*SetMinLogLevel*
 }
 
 {
@@ skipping 98 matching lines @@
   fun:MetricsService::InitTask::Run*
 }
 
 {
   bug_64188
   ThreadSanitizer:Race
   ...
   fun:base::RefCounted<net::NetLog::EventParameters>::*
 }
 
-{
-  bug_64501
-  ThreadSanitizer:Race
-  ...
-  fun:base::RefCounted<net::URLRequestThrottlerEntryInterface>::*
-}
-
 ############################
 # Benign races
 {
   bug_62694 [benign races in Histogram in CookieMonster]
   ThreadSanitizer:Race
   ...
   fun:base::Histogram::*
   fun:net::CookieMonster::*
 }
 
@@ skipping 306 matching lines @@
   ThreadSanitizer:Race
   ...
   fun:gethostbyname2_r*
 }
 
 {
   Benign race in nss (PR_EnterMonitor)
   ThreadSanitizer:Race
   fun:PR_EnterMonitor
 }