Ensure that in Desktop AURA the WindowModalityController class is at the head of the event pre targ…

Ensure that in Desktop AURA the WindowModalityController class is at the head of the event pre target handlers list.

This ensures that it handles input events first when modal windows are at the top of the Zorder.

This logic has been added to the DesktopNativeWidgetAura::InstallWindowModalityController function which is called by the
DesktopRootWindowHost implementations on windows and linux when the root window is created.

The logic in ash shell.cc has also been changed to instantiate the WindowModalityController object at the beginning. The
class WindowModalityController now takes the EventTarget as an argument in its ctor and adds itself to the pre target
list. Added a DCHECK here to check if the pre target list in the EventTarget is empty. The WindowModalityController removes
itself from the pre target list in its dtor.

BUG=299662
R=sky@chromium.org, sky
TEST=Covered by Desktop AURA widget test WindowMouseModalityTest

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=226609

[sky, 2013-10-01 17:32:12]

Also, is it possible to write a test for this? Not one that verifies order but
one that verifies modality works?

https://codereview.chromium.org/25445002/diff/1/ui/views/widget/desktop_aura/...
File ui/views/widget/desktop_aura/desktop_native_widget_aura.cc (right):

https://codereview.chromium.org/25445002/diff/1/ui/views/widget/desktop_aura/...
ui/views/widget/desktop_aura/desktop_native_widget_aura.cc:246: void
DesktopNativeWidgetAura::InstallInputMethodEventFilter(
Having a method called InstallInputMethodEventFilter install a modality
controller is rather confusing. How about a separate function that the
DesktopRootWindowHost impls call into?

[Ben Goodger (Google), 2013-10-01 17:42:54]

The order here was inspired by the ordering in src/ash/shell.cc. Is there a bug
in ash too? I'd like to understand why the two are different.

[ananta, 2013-10-01 22:37:32]

Added a Desktop AURA based widget unittest WindowMouseModalityTest which
verifies the modality behavior with mouse input.

I also changed ash shell to instantiate the modality controller at the
beginning.

https://codereview.chromium.org/25445002/diff/1/ui/views/widget/desktop_aura/...
File ui/views/widget/desktop_aura/desktop_native_widget_aura.cc (right):

https://codereview.chromium.org/25445002/diff/1/ui/views/widget/desktop_aura/...
ui/views/widget/desktop_aura/desktop_native_widget_aura.cc:246: void
DesktopNativeWidgetAura::InstallInputMethodEventFilter(
On 2013/10/01 17:32:12, sky wrote:
> Having a method called InstallInputMethodEventFilter install a modality
> controller is rather confusing. How about a separate function that the
> DesktopRootWindowHost impls call into?
Added a method InstallWindowModalityController to the DesktopNativeWidgetAura
class which is called at the beginning by the DesktopRootWindowHosts.

[sky, 2013-10-02 15:54:12]

LGTM

https://codereview.chromium.org/25445002/diff/29001/ash/shell.cc
File ash/shell.cc (right):

https://codereview.chromium.org/25445002/diff/29001/ash/shell.cc#newcode430
ash/shell.cc:430: window_modality_controller_.reset(
Add comment that order is important here.

https://codereview.chromium.org/25445002/diff/29001/ui/views/widget/desktop_a...
File ui/views/widget/desktop_aura/desktop_native_widget_aura.cc (right):

https://codereview.chromium.org/25445002/diff/29001/ui/views/widget/desktop_a...
ui/views/widget/desktop_aura/desktop_native_widget_aura.cc:212: if
(window_modality_controller_)
Document why this is explicit.

[ananta, 2013-10-02 17:46:55]

https://codereview.chromium.org/25445002/diff/29001/ash/shell.cc
File ash/shell.cc (right):

https://codereview.chromium.org/25445002/diff/29001/ash/shell.cc#newcode430
ash/shell.cc:430: window_modality_controller_.reset(
On 2013/10/02 15:54:12, sky wrote:
> Add comment that order is important here.

Done.

https://codereview.chromium.org/25445002/diff/29001/ui/views/widget/desktop_a...
File ui/views/widget/desktop_aura/desktop_native_widget_aura.cc (right):

https://codereview.chromium.org/25445002/diff/29001/ui/views/widget/desktop_a...
ui/views/widget/desktop_aura/desktop_native_widget_aura.cc:212: if
(window_modality_controller_)
On 2013/10/02 15:54:12, sky wrote:
> Document why this is explicit.

Done.

[ananta, 2013-10-02 23:17:11]

Committed patchset #3 manually as r226609 (presubmit successful).