Add CanMinimize to classes that implement WidgetDelegate::CanMaximize.

ash/shell/panel_window.cc

Index: ash/shell/panel_window.cc
diff --git a/ash/shell/panel_window.cc b/ash/shell/panel_window.cc
index 3a197a3d0747acd498e9dce91865006584d38daa..f092aa8ce376244c9b425e1a6773d303fc54544d 100644
--- a/ash/shell/panel_window.cc
+++ b/ash/shell/panel_window.cc
@@ -81,6 +81,10 @@ bool PanelWindow::CanMaximize() const {
   return false;
 }
 
+bool PanelWindow::CanMinimize() const {
+  return false;
+}
+
 views::NonClientFrameView* PanelWindow::CreateNonClientFrameView(
     views::Widget* widget) {
   return new PanelFrameView(widget, PanelFrameView::FRAME_NONE);