Lock screen for Chrome-Athena

athena/wm/window_overview_mode.cc

Index: athena/wm/window_overview_mode.cc
diff --git a/athena/wm/window_overview_mode.cc b/athena/wm/window_overview_mode.cc
index 0b16b6c2b288e519985d5ce0fa45e1adf5260a34..7a2671dc344d218420bafa3b76d04bdd25037b2b 100644
--- a/athena/wm/window_overview_mode.cc
+++ b/athena/wm/window_overview_mode.cc
@@ -430,7 +430,8 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
         targeter->FindTargetForLocatedEvent(container_, event));
     while (target && target->parent() != container_)
       target = target->parent();
-    aura::Window* transient_parent = wm::GetTransientParent(target);
+    aura::Window* transient_parent =
+        target ? wm::GetTransientParent(target) : NULL;

[Jun Mukai, 2014/10/13 18:20:24]

Not sure how it's related to the lock screen.  Could you explain a bit?

[Dmitry Polukhin, 2014/10/14 11:20:33]

I see that first keyboard or mouse event after screen lock results in target ==
NULL here that causes crash inside GetTransientParent. Morever according to loop
condition it is legal case when target is NULL (while (target &&
target->parent() != container_)).

[Jun Mukai, 2014/10/14 18:27:25]

Still don't get it. Rather than handling here, should we cancel the window
overview mode when entering to lock screen?  This code path won't be reached in
the lock screen.

[oshima, 2014/10/14 19:05:15]

I think this is a regression I introduced. I will create separate CL with a
test, but
I'm ok to land this in this CL (if my CL isn't ready).

     return transient_parent ? transient_parent : target;
   }