add suppression for race on on BrowserMainLoop::ShutdownThreadsAndCleanUp

TBR=jam@chromium.org
BUG=118319
test=waterfall.sh

Review URL: https://chromiumcodereview.appspot.com/9702060

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@126825 0039d316-1c4b-4281-b951-d872f2087c98

tools/valgrind/tsan/suppressions.txt

@@ -861,3 +861,18 @@
   fun:logging::::LoggingTest_Dcheck_Test::TestBody
   fun:testing::internal::HandleSehExceptionsInMethodIfSupported
 }
+{
+  bug_118319
+  ThreadSanitizer:Race
+  fun:content::BrowserThreadImpl::~BrowserThreadImpl
+  fun:content::BrowserProcessSubThread::~BrowserProcessSubThread
+  fun:scoped_ptr::reset
+  fun:content::BrowserMainLoop::ShutdownThreadsAndCleanUp
+  fun:::BrowserMainRunnerImpl::Shutdown
+  fun:BrowserMain
+  fun:::RunNamedProcessTypeMain
+  fun:::ContentMainRunnerImpl::Run
+  fun:content::ContentMain
+  fun:ChromeMain
+  fun:main
+}