Reland Fix Views web-modal dialog widget creation.

Reland Fix Views web-modal dialog widget creation.

The original CL was reverted in r275139 for XP test failures:
http://build.chromium.org/p/chromium.win/builders/XP%20Tests%20%281%29/builds/31455
(MediaGalleriesPlatformAppBrowserTest.Scan timeouts)
I've addressed this here by reverting a test helper:
MediaGalleriesScanResultDialogViews::AcceptDialogForTesting

r272016 regressed web-modal dialog shadow styling.
Use CreateDialogWidget for dialog creation to fix that.
Only set SHADOW_TYPE_NONE for new-style dialogs there.
(removes the double border, consolidates dialog widget init)
Take WidgetDelegate for ConstrainedWebDialogDelegateViewViews.
Mark web-modals as ui::MODAL_TYPE_CHILD and child widgets.

Remove now unused Widget::CreateWindowAsFramelessChild.
(keep a copy for the system-modal captive portal dialog)
(that dialog is very odd, system-modal and "web-modal"?)

Add [Create|Show]WebModalDialogViews helper functions.
Use these for c/b/ui/views web-modal dialog init/show.
(cannot be used by c/b/chromeos, so cleanup less there)
Cleanup includes, cached widgets, using statements, etc.

BUG=376646, 378970
TEST=Views tab-modal dialogs appear as expected.
TBR=wittman@chromium.org,sky@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=275303

[msw, 2014-06-05 19:20:44]

Take a look as you have time; fingers crossed for XP...

[msw, 2014-06-05 19:20:50]

The CQ bit was checked by msw@chromium.org

[commit-bot: I haz the power, 2014-06-05 19:22:54]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/msw@chromium.org/319013002/20001

[Mike Wittman, 2014-06-05 20:03:34]

That's unfortunate... LGTM.

[sky, 2014-06-05 22:53:54]

SLGTM

[commit-bot: I haz the power, 2014-06-06 01:24:39]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  linux_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/linux_chromium_rel/bu...)

[commit-bot: I haz the power, 2014-06-06 02:55:01]

Change committed as 275303

[vandebo (ex-Chrome), 2014-06-06 15:35:58]

Can you clarify what you mean by "I've addressed this here by reverting a test
helper:
MediaGalleriesScanResultDialogViews::AcceptDialogForTesting" ?

[msw, 2014-06-06 15:39:10]

On 2014/06/06 15:35:58, vandebo wrote:
> Can you clarify what you mean by "I've addressed this here by reverting a test
> helper:
> MediaGalleriesScanResultDialogViews::AcceptDialogForTesting" ?

Look at the only difference between the first and second patch sets:
https://codereview.chromium.org/319013002/diff2/1:20001/chrome/browser/ui/vie...
My original CL modified that function, but in this CL I have not done so.