Added a11y alert on entering overview mode

ash/wm/overview/window_overview.cc

Index: ash/wm/overview/window_overview.cc
diff --git a/ash/wm/overview/window_overview.cc b/ash/wm/overview/window_overview.cc
index da615f755825d499a2b8ac56e3706114ea6c98ee..1b3c8a951da68b0e67efbed6397e6d3b7eefa3ec 100644
--- a/ash/wm/overview/window_overview.cc
+++ b/ash/wm/overview/window_overview.cc
@@ -6,9 +6,11 @@
 
 #include <algorithm>
 
+#include "ash/accessibility_delegate.h"
 #include "ash/metrics/user_metrics_recorder.h"
 #include "ash/screen_util.h"
 #include "ash/shell.h"
+#include "ash/shell_delegate.h"

[tdanderson, 2014/04/28 15:34:39]

I don't think you need this #include.

[Nina, 2014/04/28 17:24:43]

Done.

 #include "ash/shell_window_ids.h"
 #include "ash/switchable_windows.h"
 #include "ash/wm/overview/scoped_transform_overview_window.h"
@@ -148,6 +150,8 @@ WindowOverview::WindowOverview(WindowSelector* window_selector,
   shell->PrependPreTargetHandler(this);
   shell->metrics()->RecordUserMetricsAction(UMA_WINDOW_OVERVIEW);
   HideAndTrackNonOverviewWindows();
+  Shell::GetInstance()->accessibility_delegate()->TriggerAccessibilityAlert(

[tdanderson, 2014/04/28 15:34:39]

Is accessibility_delegate() guaranteed to be non-NULL here?

[Nina, 2014/04/28 17:24:43]

Apparently yes

+             A11Y_ALERT_WINDOW_OVERVIEW_STARTING);

[tdanderson, 2014/04/28 15:34:39]

Indent should be length 4 here.

[Nina, 2014/04/28 17:24:43]

Done.

 }
 
 WindowOverview::~WindowOverview() {