Add always-on-top property to app windows

The chrome.app.window API has been extended to include:
- A new alwaysOnTop option for the create() function.
- An AppWindow.isAlwaysOnTop() function to query the state of this
property.
- An AppWindow.setAlwaysOnTop() function to change this property after
creation of the window.

Changes involving native app windows:
- Added apps::NativeAppWindow::SetAlwaysOnTop().
- Implemented IsAlwaysOnTop(), a function inherited from ui::BaseWindow
but was left unimplemented for native app windows.

Changes involving views:
- Added IsAlwaysOnTop(). SetAlwaysOnTop() already existed.

BUG=171597
TEST=browser_tests (PlatformAppBrowserTest.WindowsApiAlwaysOnTop).
Test manually by creating an app that enables the alwaysOnTop option
on window creation and changes the property after creation.
Test Windows, Mac, ChromeOS and Linux.

Review URL: https://codereview.chromium.org/26427002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228160 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 4 insertions, 0 deletions

diff --git a/ui/views/widget/widget.h b/ui/views/widget/widget.h
index 151d2f3..3ff89e4 100644
--- a/ui/views/widget/widget.h
+++ b/ui/views/widget/widget.h
@@ -461,6 +461,10 @@ class VIEWS_EXPORT Widget : public internal::NativeWidgetDelegate,
   // Sets the widget to be on top of all other widgets in the windowing system.
   void SetAlwaysOnTop(bool on_top);
 
+  // Returns whether the widget has been set to be on top of most other widgets
+  // in the windowing system.
+  bool IsAlwaysOnTop() const;
+
   // Maximizes/minimizes/restores the window.
   void Maximize();
   void Minimize();