Add simple mash context menu support.

ash/mus/shell_delegate_mus.h

Index: ash/mus/shell_delegate_mus.h
diff --git a/ash/mus/shell_delegate_mus.h b/ash/mus/shell_delegate_mus.h
index 804663dc2f69c998ecdf43eed9bc3c05561db761..545f7ccc2e8e23b5356c02628ea6e09b74d2d441 100644
--- a/ash/mus/shell_delegate_mus.h
+++ b/ash/mus/shell_delegate_mus.h
@@ -15,12 +15,16 @@ namespace keyboard {
 class KeyboardUI;
 }
 
+namespace mojo {
+class Connector;
+}
+
 namespace ash {
 namespace sysui {
 
 class ShellDelegateMus : public ash::ShellDelegate {
  public:
-  ShellDelegateMus();
+  explicit ShellDelegateMus(mojo::Connector* connector);
   ~ShellDelegateMus() override;
 
   bool IsFirstRunAfterBoot() const override;
@@ -53,6 +57,8 @@ class ShellDelegateMus : public ash::ShellDelegate {
   gfx::Image GetDeprecatedAcceleratorImage() const override;
 
  private:
+  mojo::Connector* connector_;
+
   DISALLOW_COPY_AND_ASSIGN(ShellDelegateMus);
 };