Downloads: replace BrowserThread::FILE with task scheduler.

chrome/browser/download/download_browsertest.cc

Index: chrome/browser/download/download_browsertest.cc
diff --git a/chrome/browser/download/download_browsertest.cc b/chrome/browser/download/download_browsertest.cc
index 73ad71faf517d679c94d1b9780b007e079a30073..96f174f93fdf215f950d0fd277af7275cd1634da 100644
--- a/chrome/browser/download/download_browsertest.cc
+++ b/chrome/browser/download/download_browsertest.cc
@@ -916,7 +916,7 @@ class DownloadTest : public InProcessBrowserTest {
     }
 
     // Wait till the |DownloadFile|s are destroyed.
-    content::RunAllPendingInMessageLoop(content::BrowserThread::FILE);
+    content::RunAllBlockingPoolTasksUntilIdle();
     content::RunAllPendingInMessageLoop(content::BrowserThread::UI);

[gab, 2017/07/20 16:54:31]

Can remove this line too as RunAllBlockingPoolTasksUntilIdle() does both (I know
it's poorly named, we  have TODO to rename it but will wait until after
migration to avoid causing merge conflicts for everyone working on migration..)

[Sigurður Ásgeirsson, 2017/07/20 17:23:21]

Done.

 
     // Validate that the correct files were downloaded.