mus: Implement Window Server Capture

components/mus/public/cpp/window.h

Index: components/mus/public/cpp/window.h
diff --git a/components/mus/public/cpp/window.h b/components/mus/public/cpp/window.h
index 21661c20d2ce5d4585c9f6a7d196cc40dda446e9..0377497ea410b56da5fbe0a743ffae3046c3df46 100644
--- a/components/mus/public/cpp/window.h
+++ b/components/mus/public/cpp/window.h
@@ -190,6 +190,10 @@ class Window {
   void SetTextInputState(mojo::TextInputStatePtr state);
   void SetImeVisibility(bool visible, mojo::TextInputStatePtr state);
 
+  bool has_capture() const { return has_capture_; }
+  void SetCapture();
+  void ReleaseCapture();
+
   // Focus.
   void SetFocus();
   bool HasFocus() const;
@@ -242,6 +246,7 @@ class Window {
   // Returns true if the order actually changed.
   bool LocalReorder(Window* relative, mojom::OrderDirection direction);
   void LocalSetBounds(const gfx::Rect& old_bounds, const gfx::Rect& new_bounds);
+  void LocalSetCapture(bool capture);
   void LocalSetClientArea(
       const gfx::Insets& new_client_area,
       const std::vector<gfx::Rect>& additional_client_areas);
@@ -303,6 +308,7 @@ class Window {
   mojom::ViewportMetricsPtr viewport_metrics_;
 
   bool visible_;
+  bool has_capture_;
 
   mojom::Cursor cursor_id_;