Remove TransparentActivateWindowButton from Overview Mode

ash/wm/overview/scoped_transform_overview_window.cc

Index: ash/wm/overview/scoped_transform_overview_window.cc
diff --git a/ash/wm/overview/scoped_transform_overview_window.cc b/ash/wm/overview/scoped_transform_overview_window.cc
index 5d2734d21acd59045003906424133a33e22bc221..a3ebe83cf2cbab43f440fcfd09f3d0b869e4ea20 100644
--- a/ash/wm/overview/scoped_transform_overview_window.cc
+++ b/ash/wm/overview/scoped_transform_overview_window.cc
@@ -166,8 +166,6 @@ TransientDescendantIteratorRange GetTransientTreeIterator(
 ScopedTransformOverviewWindow::ScopedTransformOverviewWindow(
         aura::Window* window)
     : window_(window),
-      activate_button_(new TransparentActivateWindowButton(
-          window_->GetRootWindow(), this)),
       minimized_(window->GetProperty(aura::client::kShowStateKey) ==
                  ui::SHOW_STATE_MINIMIZED),
       ignored_by_shelf_(wm::GetWindowState(window)->ignored_by_shelf()),
@@ -304,10 +302,6 @@ void ScopedTransformOverviewWindow::SetOpacity(float opacity) {
   }
 }
 
-void ScopedTransformOverviewWindow::Select() {
-  wm::GetWindowState(window_)->Activate();
-}
-
 void ScopedTransformOverviewWindow::Close() {
   aura::Window* window = GetTransientRoot(window_);
   views::Widget::GetWidgetForNativeView(window)->Close();