MacViews: Implement Window-modal dialogs using sheets

These are used, e.g., for the Bookmark -> Edit... dialogs on Cocoa and
Views.

This gets WidgetTestInteractive.*Window*ModalWindowDestroyedActivationTest
passing.

WidgetTestInteractive.*System*ModalWindowReleasesCapture is disabled in
this CL. System modal windows are not needed on Mac.

Currently the implementation on MacViews assumes all modal dialogs are
shown using a sheet. On Cocoa, this is not always true for
WebContents-Modal dialogs (e.g. cookies and site data), but it is true
for some WebContents-Modal dialogs (e.g. certificate information).

A follow-up will add logic to ensure WebContents-Modal dialogs are
handled appropriately, and have good test coverage.

After this all tests pass on the current mac trybot configuration with
toolkit_views=1.

BUG=403679

Review URL: https://codereview.chromium.org/993253002

Cr-Commit-Position: refs/heads/master@{#320977}

1 files changed, 1 insertions, 0 deletions

diff --git a/ui/views/examples/widget_example.h b/ui/views/examples/widget_example.h
index 159a4da..87065f9 100644
--- a/ui/views/examples/widget_example.h
+++ b/ui/views/examples/widget_example.h
@@ -30,6 +30,7 @@ class VIEWS_EXAMPLES_EXPORT WidgetExample : public ExampleBase,
   enum Command {
     POPUP,        // Show a popup widget.
     DIALOG,       // Show a dialog widget.
+    MODAL_DIALOG, // Show a modal dialog widget.
     CHILD,        // Show a child widget.
     CLOSE_WIDGET, // Close the sender button's widget.
   };