TSAN: Stop PollingThread before deleting it to avoid race on changing virtual table.

BUG=139849

Review URL: https://chromiumcodereview.appspot.com/10828105

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@149370 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/device_orientation/provider_impl.cc

@@ -31,6 +31,7 @@ bool IsElementSignificantlyDifferent(bool can_provide_element1,
 }
 
 void DeleteThread(base::Thread* thread) {
+  thread->Stop();
   delete thread;
 }
 

tools/valgrind/tsan/suppressions.txt

@@ -1029,11 +1029,3 @@
    fun:browser_sync::NewNonFrontendDataTypeController::StartAssociationWithSharedChangeProcessor
    fun:base::internal::RunnableAdapter::Run
 }
-{
-  bug_139849
-  ThreadSanitizer:Race
-  fun:base::Thread::~Thread
-  fun:device_orientation::ProviderImpl::PollingThread::~PollingThread
-  fun:::DeleteThread
-  fun:base::internal::RunnableAdapter::Run
-}