Remove call to MessageLoop::RunUntilIdle from wait_util.mm.

ios/chrome/browser/reading_list/url_downloader_unittest.cc

Index: ios/chrome/browser/reading_list/url_downloader_unittest.cc
diff --git a/ios/chrome/browser/reading_list/url_downloader_unittest.cc b/ios/chrome/browser/reading_list/url_downloader_unittest.cc
index 14ee119ac500fb8b0f5f734bb13e49848576cdfd..cbaec79ecf67e64b27436bac249dbebf3e374085 100644
--- a/ios/chrome/browser/reading_list/url_downloader_unittest.cc
+++ b/ios/chrome/browser/reading_list/url_downloader_unittest.cc
@@ -8,7 +8,6 @@
 
 #include "base/files/file_util.h"
 #import "base/mac/bind_objc_block.h"
-#include "base/message_loop/message_loop.h"
 #include "base/path_service.h"
 #include "base/run_loop.h"
 #import "base/test/ios/wait_util.h"
@@ -109,9 +108,7 @@ class URLDownloaderTest : public testing::Test {
   }
 
   void WaitUntilCondition(ConditionBlock condition) {
-    base::MessageLoop* messageLoop = base::MessageLoop::current();
-    DCHECK(messageLoop);
-    base::test::ios::WaitUntilCondition(condition, messageLoop,
+    base::test::ios::WaitUntilCondition(condition, true,
                                         base::TimeDelta::FromSeconds(1));
   }
 };