Revert "Reland #3: Switch WindowedNotificationObserver to use base::RunLoop."

This reverts commit 54fcb75f.

Reason for revert: landed too early and causing flakes

Original change's description:
> Reland #3: Switch WindowedNotificationObserver to use base::RunLoop.
> 
> Now it will quit the message loop immediately after receiving the
> notification. Also it does not allow nested tasks anymore.
> 
> Bug: 668707
> Change-Id: I8d8a0ffb073236c3bbd00877bd48cc496b1c5036
> Reviewed-on: https://chromium-review.googlesource.com/982612
> Reviewed-by: John Abd-El-Malek <jam@chromium.org>
> Reviewed-by: Gabriel Charette <gab@chromium.org>
> Commit-Queue: Alexander Semashko <ahest@yandex-team.ru>
> Cr-Commit-Position: refs/heads/master@{#576110}

TBR=gab@chromium.org,jam@chromium.org,ahest@yandex-team.ru

Change-Id: Ibc82b94b56e77bb9914c74517dd9f755527544f6
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 668707
Reviewed-on: https://chromium-review.googlesource.com/1143740Reviewed-by: Gabriel Charette <gab@chromium.org>
Commit-Queue: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576519}

content/public/test/test_utils.cc

@@ -319,26 +319,33 @@ void MessageLoopRunner::Quit() {
 WindowedNotificationObserver::WindowedNotificationObserver(
     int notification_type,
     const NotificationSource& source)
-    : source_(NotificationService::AllSources()) {
+    : seen_(false),
+      running_(false),
+      source_(NotificationService::AllSources()) {
   AddNotificationType(notification_type, source);
 }
 
 WindowedNotificationObserver::WindowedNotificationObserver(
     int notification_type,
     const ConditionTestCallback& callback)
-    : callback_(callback), source_(NotificationService::AllSources()) {
+    : seen_(false),
+      running_(false),
+      callback_(callback),
+      source_(NotificationService::AllSources()) {
   AddNotificationType(notification_type, source_);
 }
 
 WindowedNotificationObserver::WindowedNotificationObserver(
     int notification_type,
     const ConditionTestCallbackWithoutSourceAndDetails& callback)
-    : callback_(base::Bind(&IgnoreSourceAndDetails, callback)),
+    : seen_(false),
+      running_(false),
+      callback_(base::Bind(&IgnoreSourceAndDetails, callback)),
       source_(NotificationService::AllSources()) {
   registrar_.Add(this, notification_type, source_);
 }
 
-WindowedNotificationObserver::~WindowedNotificationObserver() = default;
+WindowedNotificationObserver::~WindowedNotificationObserver() {}
 
 void WindowedNotificationObserver::AddNotificationType(
     int notification_type,
@@ -347,21 +354,30 @@ void WindowedNotificationObserver::AddNotificationType(
 }
 
 void WindowedNotificationObserver::Wait() {
-  if (!seen_)
-    run_loop_.Run();
+  if (seen_)
+    return;
+
+  running_ = true;
+  message_loop_runner_ = new MessageLoopRunner;
+  message_loop_runner_->Run();
   EXPECT_TRUE(seen_);
 }
 
-void WindowedNotificationObserver::Observe(int type,
-                                           const NotificationSource& source,
-                                           const NotificationDetails& details) {
+void WindowedNotificationObserver::Observe(
+    int type,
+    const NotificationSource& source,
+    const NotificationDetails& details) {
   source_ = source;
   details_ = details;
   if (!callback_.is_null() && !callback_.Run(source, details))
     return;
 
   seen_ = true;
-  run_loop_.Quit();
+  if (!running_)
+    return;
+
+  message_loop_runner_->Quit();
+  running_ = false;
 }
 
 InProcessUtilityThreadHelper::InProcessUtilityThreadHelper()

content/public/test/test_utils.h

@@ -251,14 +251,15 @@ class WindowedNotificationObserver : public NotificationObserver {
                const NotificationDetails& details) override;
 
  private:
-  bool seen_ = false;
+  bool seen_;
+  bool running_;
   NotificationRegistrar registrar_;
 
   ConditionTestCallback callback_;
 
   NotificationSource source_;
   NotificationDetails details_;
-  base::RunLoop run_loop_;
+  scoped_refptr<MessageLoopRunner> message_loop_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowedNotificationObserver);
 };