mus: Implement Window Server Capture

components/mus/display_manager.h

Index: components/mus/display_manager.h
diff --git a/components/mus/display_manager.h b/components/mus/display_manager.h
index 4173f367b0f1ba75aba182d11a00b89fa9450a83..9a7a8ba27590547e2fe9bb9d56ee09e4c7234467 100644
--- a/components/mus/display_manager.h
+++ b/components/mus/display_manager.h
@@ -65,6 +65,8 @@ class DisplayManager {
 
   virtual void SetTitle(const base::string16& title) = 0;
 
+  virtual void SetCapture() = 0;
+
   virtual const mojo::ViewportMetrics& GetViewportMetrics() = 0;
 
   virtual void UpdateTextInputState(const ui::TextInputState& state) = 0;
@@ -97,6 +99,7 @@ class DefaultDisplayManager : public DisplayManager,
   void SchedulePaint(const ServerView* view, const gfx::Rect& bounds) override;
   void SetViewportSize(const gfx::Size& size) override;
   void SetTitle(const base::string16& title) override;
+  void SetCapture() override;
   const mojo::ViewportMetrics& GetViewportMetrics() override;
   void UpdateTextInputState(const ui::TextInputState& state) override;
   void SetImeVisibility(bool visible) override;