mus: Implement Window Server Capture

components/mus/view_tree_impl.cc

Index: components/mus/view_tree_impl.cc
diff --git a/components/mus/view_tree_impl.cc b/components/mus/view_tree_impl.cc
index b97583e1fbf1b804651bc5491cd63a145e011539..08f109770d064bd444e859945ce7a747805b46d3 100644
--- a/components/mus/view_tree_impl.cc
+++ b/components/mus/view_tree_impl.cc
@@ -318,6 +318,10 @@ void ViewTreeImpl::ProcessFocusChanged(const ServerView* old_focused_view,
                                : ViewIdToTransportId(ViewId()));
 }
 
+void ViewTreeImpl::ProcessLostCapture(const ServerView* old_captured_view) {
+  client()->OnLostCapture(ViewIdToTransportId(old_captured_view->id()));
+}
+
 bool ViewTreeImpl::IsViewKnown(const ServerView* view) const {
   return known_views_.count(ViewIdToTransportId(view->id())) > 0;
 }
@@ -567,6 +571,18 @@ void ViewTreeImpl::GetViewTree(
   callback.Run(ViewsToViewDatas(views));
 }
 
+void ViewTreeImpl::SetCapture(Id view_id,
+                              const Callback<void(bool)>& callback) {
+  ServerView* view = GetView(ViewIdFromTransportId(view_id));
+  bool success = view && access_policy_->CanSetCapture(view);
+  if (success) {
+    ViewTreeHostImpl* host = GetHost();
+    if (host)
+      host->SetCapture(view);
+  }
+  callback.Run(success);
+}
+
 void ViewTreeImpl::SetViewBounds(Id view_id,
                                  mojo::RectPtr bounds,
                                  const Callback<void(bool)>& callback) {