ash: Do a null-check for the screen-position client.

ash: Do a null-check for the screen-position client.

In a multi-monitor setup, when switching from extended mode to mirror mode,
it is possible for the external monitor to receive events between when its
RootWindowController is Shutdown()ed (which destroyes the screen-position
client) and the root-window is destroyed. So make sure the client is there
before trying to use it to convert the event's location to screen space.

BUG=358266
R=oshima@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=271100

[oshima, 2014-05-16 19:13:05]

On 2014/05/16 17:43:24, sadrul wrote:

I see. You might have affected by this cleanup.
https://codereview.chromium.org/196573023
I probably should bring PrepareForShutdown back to ash (via AshWindowTreeHost).
This CL lgtm.
I may remove this when I do that, just FYI.

[sadrul, 2014-05-16 21:31:21]

Committed patchset #1 manually as r271100 (presubmit successful).