Flush TaskScheduler in content::RunAllBlockingPoolTasksUntilIdle().

content/public/test/test_utils.cc

Index: content/public/test/test_utils.cc
diff --git a/content/public/test/test_utils.cc b/content/public/test/test_utils.cc
index 4afe2321e9f3f4c021831dc3857db3582e9991a7..95c8d987d619b0c124c2b2b2ace9c2c2a43492cb 100644
--- a/content/public/test/test_utils.cc
+++ b/content/public/test/test_utils.cc
@@ -13,6 +13,7 @@
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/task_scheduler/task_scheduler.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/values.h"
@@ -157,8 +158,13 @@ void RunAllPendingInMessageLoop(BrowserThread::ID thread_id) {
 
 void RunAllBlockingPoolTasksUntilIdle() {
   while (true) {
+    // Flush blocking pool tasks.

[robliao, 2017/03/17 01:00:14]

Remove this comment as it's stating what the next line does.

Alternatively, you can have a banner comment that discusses the postcondition of
this function (all inflight tasks are done at the end of this call and enumerate
the sources).

An interesting non-obvious comment would be why we do this with the MessageLoop
in the third section as we've just dealt with the BlockingPool.

[fdoray, 2017/03/31 20:26:04]

Removed unnecessary comment.

I have a few CLs to land:
1. Flush TaskScheduler in RunAllBlockingPoolTasksUntilIdle (this CL).
2. Always use an async TaskScheduler in TestBrowserThreadBundle.
3. Enable redirection of SequencedWorkerPool to TaskScheduler in
TestBrowserThreadBundle.
4. Remove content::BrowserThread::GetBlockingPool()->FlushForTesting(); from
this function.

I'd like to wait until 4. to work on the comments in this function, because
they'll have to be updated anyways.

     content::BrowserThread::GetBlockingPool()->FlushForTesting();
 
+    // Also flush TaskScheduler tasks since all blocking pool call sites are
+    // being migrated to TaskScheduler.
+    base::TaskScheduler::GetInstance()->FlushForTesting();
+
     TaskObserver task_observer;
     base::MessageLoop::current()->AddTaskObserver(&task_observer);
     base::RunLoop().RunUntilIdle();