Added ignored_by_shelf bit to overview mode selection widget.

ash/wm/overview/window_grid.cc

Index: ash/wm/overview/window_grid.cc
diff --git a/ash/wm/overview/window_grid.cc b/ash/wm/overview/window_grid.cc
index 796684993bba32ef4fb5128bb57bcd0733eee291..99ea37c2d1e54056e20674b2f1366eb468a595f8 100644
--- a/ash/wm/overview/window_grid.cc
+++ b/ash/wm/overview/window_grid.cc
@@ -358,6 +358,10 @@ void WindowGrid::InitSelectionWidget(WindowSelector::Direction direction) {
   // Disable the "bounce in" animation when showing the window.
   ::wm::SetWindowVisibilityAnimationTransition(
       selection_widget_->GetNativeWindow(), ::wm::ANIMATE_NONE);
+  // The selection widget should not activate the shelf when passing under it.
+  ash::wm::GetWindowState(selection_widget_->GetNativeWindow())->
+      set_ignored_by_shelf(true);
+
   views::View* content_view = new views::View;
   content_view->set_background(
       views::Background::CreateSolidBackground(kWindowOverviewSelectionColor));