Make memory-infra tests register / unregister with thread safety

content/browser/tracing/memory_tracing_browsertest.cc

Index: content/browser/tracing/memory_tracing_browsertest.cc
diff --git a/content/browser/tracing/memory_tracing_browsertest.cc b/content/browser/tracing/memory_tracing_browsertest.cc
index c015532545d76bb436d9cd4ae7197d66926fb9cc..fe966660829131db6aa2442692f1e5c05a707fd4 100644
--- a/content/browser/tracing/memory_tracing_browsertest.cc
+++ b/content/browser/tracing/memory_tracing_browsertest.cc
@@ -103,8 +103,8 @@ class MemoryTracingTest : public ContentBrowserTest {
   }
 
   void TearDown() override {
-    MemoryDumpManager::GetInstance()->UnregisterDumpProvider(
-        mock_dump_provider_.get());
+    MemoryDumpManager::GetInstance()->UnregisterAndDeleteDumpProviderSoon(
+        std::move(mock_dump_provider_));
     mock_dump_provider_.reset();
     ContentBrowserTest::TearDown();
   }