Fix mouse lock on chromeos

Fix mouse lock on chromeos
* CompoundEventFilter should show cursor only if the cursor was hidden by this event filter.
* CompoundEventFilter shouldn't try to hide if it's already hidden by someone else.
* It no longer needs set_update_cursor_visibility.
* There is one edge case where it leaves cursor visible. Cursor is hidden by the CompoundEventFilter, then again hidden by mouse lock. I changed RWHVA to hide the cursor if it's visible when mouse is moved.

BUG=152319
TEST=updated test case. also tested manually: see bug for repro step.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=158845

[oshima, 2012-09-26 08:47:20]

I looked into possibility to lock in ShowCursor, but it looked risky to me
(especially because this has to be merged to 23) for following reasons:

a) ShowCursor is not necessarily paired with true and false
b) It has impact on current Lock/Unlock behavior. (Unlock may show the cursor)

I believe this is still doable but also think this is too riskly to merge to 23.

Hence this alternative CL. This is much simpler and low risk to merge. I'll look
into the above approach for 24 or 25.

[sky, 2012-09-26 13:42:03]

LGTM

http://codereview.chromium.org/10982040/diff/11002/ui/aura/shared/compound_ev...
File ui/aura/shared/compound_event_filter.h (right):

http://codereview.chromium.org/10982040/diff/11002/ui/aura/shared/compound_ev...
ui/aura/shared/compound_event_filter.h:61: // |update_cursor_visibility_| is
true.
Update comment.

[oshima, 2012-09-26 15:18:00]

http://codereview.chromium.org/10982040/diff/11002/ui/aura/shared/compound_ev...
File ui/aura/shared/compound_event_filter.h (right):

http://codereview.chromium.org/10982040/diff/11002/ui/aura/shared/compound_ev...
ui/aura/shared/compound_event_filter.h:61: // |update_cursor_visibility_| is
true.
On 2012/09/26 13:42:04, sky wrote:
> Update comment.

Done.

[commit-bot: I haz the power, 2012-09-26 15:18:10]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/oshima@chromium.org/10982040/12001

[scheib, 2012-09-26 15:54:58]

Thanks for the quick fix. Do you think there is a chance of flicker when the
mouse is locked and hidden, but other events attempt to make it visible?

lgtm.

[oshima, 2012-09-26 16:23:54]

On 2012/09/26 15:54:58, scheib wrote:
> Thanks for the quick fix. Do you think there is a chance of flicker when the
> mouse is locked and hidden, but other events attempt to make it visible?
> 
> lgtm.

There are only a few places that (rarely) calls ShowCursor(), so  the chance is
pretty small
In addition, we hide a cursor upon MouseEvent (in the same UI thread execution
), 
so I think most user won't notice it.

[commit-bot: I haz the power, 2012-09-26 19:09:59]

Change committed as 158845