Fix use-after-free issues in UpgradeDetectorImplTest.

chrome/browser/upgrade_detector_impl_unittest.cc

Index: chrome/browser/upgrade_detector_impl_unittest.cc
diff --git a/chrome/browser/upgrade_detector_impl_unittest.cc b/chrome/browser/upgrade_detector_impl_unittest.cc
index 9646b894f42ca2664c997cd41d4348adf2f2e201..76caf106b7ef7d77f62a1f466b86c0b74d41deba 100644
--- a/chrome/browser/upgrade_detector_impl_unittest.cc
+++ b/chrome/browser/upgrade_detector_impl_unittest.cc
@@ -7,11 +7,13 @@
 #include <vector>
 
 #include "base/macros.h"
+#include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/test/test_browser_thread_bundle.h"
+#include "content/public/test/test_utils.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 class TestUpgradeDetectorImpl : public UpgradeDetectorImpl {
@@ -88,6 +90,9 @@ TEST(UpgradeDetectorImplTest, VariationsChanges) {
   EXPECT_EQ(chrome::NOTIFICATION_UPGRADE_RECOMMENDED,
             notifications_listener.notifications_received().front());
   EXPECT_EQ(0, detector.trigger_critical_update_call_count());
+
+  // Run pending checks.

[Nico, 2016/12/21 03:55:59]

This isn't a good comment since it just answers "what?" and repeats the next
line. Instead, answer "why?": "// Execute tasks sent to FILE thread by
|detector| referencing it while it's still in scope" or similar

[krasin1, 2016/12/21 04:05:21]

Good point. Done.

+  content::RunAllPendingInMessageLoop(content::BrowserThread::FILE);
 }
 
 TEST(UpgradeDetectorImplTest, VariationsCriticalChanges) {
@@ -109,4 +114,7 @@ TEST(UpgradeDetectorImplTest, VariationsCriticalChanges) {
   EXPECT_EQ(chrome::NOTIFICATION_UPGRADE_RECOMMENDED,
             notifications_listener.notifications_received().front());
   EXPECT_EQ(1, detector.trigger_critical_update_call_count());
+
+  // Run pending checks.
+  content::RunAllPendingInMessageLoop(content::BrowserThread::FILE);

[Nico, 2016/12/21 03:55:59]

ditto

[krasin1, 2016/12/21 04:05:22]

Done.

 }