Plugin Power Saver: Implement pixel tests for plugin placeholders.

chrome/test/base/ui_test_utils.cc

Index: chrome/test/base/ui_test_utils.cc
diff --git a/chrome/test/base/ui_test_utils.cc b/chrome/test/base/ui_test_utils.cc
index cfa65023b18a41a1567aad26b6d5e500621cb714..53cbd29787484bb547695eb4d5b0d8e6c76f3b83 100644
--- a/chrome/test/base/ui_test_utils.cc
+++ b/chrome/test/base/ui_test_utils.cc
@@ -405,6 +405,23 @@ void GetCookies(const GURL& url,
   }
 }
 
+bool RunLoopUntil(const base::Callback<bool()>& condition) {
+  const base::TimeTicks start_time = base::TimeTicks::Now();
+  while (!condition.Run()) {
+    const base::TimeTicks current_time = base::TimeTicks::Now();
+    if (current_time - start_time > base::TimeDelta::FromSeconds(5)) {
+      ADD_FAILURE() << "Condition not met within five seconds.";
+      return false;
+    }
+
+    base::MessageLoop::current()->task_runner()->PostDelayedTask(
+        FROM_HERE, base::MessageLoop::QuitWhenIdleClosure(),
+        base::TimeDelta::FromMilliseconds(20));
+    content::RunMessageLoop();
+  }
+  return true;
+}
+
 WindowedTabAddedNotificationObserver::WindowedTabAddedNotificationObserver(
     const content::NotificationSource& source)
     : WindowedNotificationObserver(chrome::NOTIFICATION_TAB_ADDED, source),