Fix race condition where the items on ResourceContext's UserData map were rewritten to the same val…

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 # running overnight and removing outdated bugs/suppressions.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 840 matching lines @@
 }
 {
   bug_115540
   ThreadSanitizer:Race
   fun:base::Thread::message_loop
   fun:content::BrowserThreadImpl::PostTaskHelper
   fun:content::BrowserThread::PostTask
   fun:AudioRendererHost::OnCreated
   fun:media::AudioOutputController::DoCreate
 }
-{
-  bug_115678_a
-  ThreadSanitizer:Race
-  fun:*ptr::get
-  ...
-  fun:base::UserDataAdapter::Get
-  ...
-  fun:ProfileIOData::LazyInitialize
-  fun:ProfileIOData::ResourceContext::EnsureInitialized
-  fun:ProfileIOData::ResourceContext::GetRequestContext
-}
-{
-  bug_115678_b
-  ThreadSanitizer:Race
-  ...
-  fun:base::SupportsUserData::SetUserData
-  fun:content::InitializeResourceContext
-  fun:content::BrowserContext::EnsureResourceContextInitialized
-  fun:ProfileIOData::InitializeOnUIThread
-  fun:OffTheRecordProfileIOData::Handle::LazyInitialize
-  fun:OffTheRecordProfileIOData::Handle::GetChromeURLDataManagerBackendGetter
-  fun:OffTheRecordProfileImpl::GetChromeURLDataManager
-  fun:OffTheRecordProfileImpl::Init
-  fun:Profile::CreateOffTheRecordProfile
-  fun:ProfileImpl::GetOffTheRecordProfile
-  fun:Browser::NewIncognitoWindow
-}