aura: Make sure the desktop is initialized when creating a DefaultMonitorInfoProvider.

chrome/browser/notifications/desktop_notifications_unittest.cc

Index: chrome/browser/notifications/desktop_notifications_unittest.cc
diff --git a/chrome/browser/notifications/desktop_notifications_unittest.cc b/chrome/browser/notifications/desktop_notifications_unittest.cc
index b3470cdffbb8998694149c0e443848059aef1d9c..4f1a09bf81370fdbb0d757902df18eb26248cafc 100644
--- a/chrome/browser/notifications/desktop_notifications_unittest.cc
+++ b/chrome/browser/notifications/desktop_notifications_unittest.cc
@@ -11,6 +11,10 @@
 #include "chrome/test/base/testing_pref_service.h"
 #include "content/public/common/show_desktop_notification_params.h"
 
+#if defined(USE_AURA)
+#include "ui/aura/desktop.h"
+#endif
+
 using content::BrowserThread;
 
 // static
@@ -84,6 +88,12 @@ DesktopNotificationsTest::~DesktopNotificationsTest() {
 }
 
 void DesktopNotificationsTest::SetUp() {
+#if defined(USE_AURA)
+  // MockBalloonCollection retrieves information about the screen on creation.
+  // So it is necessary to make sure the desktop gets created first.
+  aura::Desktop::GetInstance();
+#endif
+
   browser::RegisterLocalState(&local_state_);
   profile_.reset(new TestingProfile());
   balloon_collection_ = new MockBalloonCollection();