Do not flush main thread tasks in ~ScopedTaskEnvironment.

base/test/scoped_task_environment.h

Index: base/test/scoped_task_environment.h
diff --git a/base/test/scoped_task_environment.h b/base/test/scoped_task_environment.h
index 7b7180ae83292b2ed67b47c906f4a8b257637b31..fe7385ea477b14f9079568d52846a197308c5541 100644
--- a/base/test/scoped_task_environment.h
+++ b/base/test/scoped_task_environment.h
@@ -63,9 +63,8 @@ class ScopedTaskEnvironment {
   ScopedTaskEnvironment(
       MainThreadType main_thread_type = MainThreadType::DEFAULT);
 
-  // Runs pending (Thread|Sequenced)TaskRunnerHandle tasks and pending
-  // BLOCK_SHUTDOWN TaskScheduler tasks. Then, unregisters the TaskScheduler and
-  // the (Thread|Sequenced)TaskRunnerHandle.
+  // Waits until no undelayed TaskScheduler tasks remain. Then, unregisters the
+  // TaskScheduler and the (Thread|Sequenced)TaskRunnerHandle.
   ~ScopedTaskEnvironment();
 
   // Synchronously runs (Thread|Sequenced)TaskRunnerHandle tasks until no