aura: Dispatch touch-events targetted to the root-window properly.

ui/aura/root_window.cc

Index: ui/aura/root_window.cc
diff --git a/ui/aura/root_window.cc b/ui/aura/root_window.cc
index 9c22cbe20083e1da2e677cf2bd52f793f7be879e..d78600dfabce5a215b975018e183378522868696 100644
--- a/ui/aura/root_window.cc
+++ b/ui/aura/root_window.cc
@@ -875,6 +875,8 @@ bool RootWindow::OnHostTouchEvent(ui::TouchEvent* event) {
   if (!target && !bounds().Contains(event->location())) {
     // If the initial touch is outside the root window, target the root.
     target = this;
+    status = ProcessTouchEvent(target, event);
+    CHECK_EQ(ui::TOUCH_STATUS_UNKNOWN, status);
   } else {
     // We only come here when the first contact was within the root window.
     if (!target) {