Ignore fullscreen windows which are behind other windows for fullscreen mode.

chrome/browser/notifications/fullscreen_notification_blocker.cc

Index: chrome/browser/notifications/fullscreen_notification_blocker.cc
diff --git a/chrome/browser/notifications/fullscreen_notification_blocker.cc b/chrome/browser/notifications/fullscreen_notification_blocker.cc
index bbfa5825abc6c5028453bc0868bb84e7d4096f76..1d23ea1e1737723797435a3cbe595d452466579e 100644
--- a/chrome/browser/notifications/fullscreen_notification_blocker.cc
+++ b/chrome/browser/notifications/fullscreen_notification_blocker.cc
@@ -33,7 +33,7 @@ bool DoesFullscreenModeBlockNotifications() {
     // Block notifications if the shelf is hidden because of a fullscreen
     // window.
     const aura::Window* fullscreen_window =
-        controller->GetTopmostFullscreenWindow();
+        controller->GetWindowForFullscreenMode();
     if (!fullscreen_window)
       return false;
     return ash::wm::GetWindowState(fullscreen_window)->