Fix for BrowserThreadTest tests

content/browser/browser_thread_unittest.cc

Index: content/browser/browser_thread_unittest.cc
diff --git a/content/browser/browser_thread_unittest.cc b/content/browser/browser_thread_unittest.cc
index 71cd598236d48faa34b99602ace654d57e3b0eb8..68f6a96425e4775a929bfd2c71792d1e0a9b24cd 100644
--- a/content/browser/browser_thread_unittest.cc
+++ b/content/browser/browser_thread_unittest.cc
@@ -40,6 +40,10 @@ class BrowserThreadTest : public testing::Test {
   void TearDown() override {
     StopUIThread();
     file_thread_->Stop();
+    ui_thread_ = nullptr;
+    file_thread_ = nullptr;
+    BrowserThreadImpl::ResetGlobalsForTesting(BrowserThread::UI);
+    BrowserThreadImpl::ResetGlobalsForTesting(BrowserThread::FILE);
   }
 
   static void BasicFunction(base::MessageLoop* message_loop) {