mus Window Server: implement event capture

components/mus/ws/window_tree_host_impl.cc

Index: components/mus/ws/window_tree_host_impl.cc
diff --git a/components/mus/ws/window_tree_host_impl.cc b/components/mus/ws/window_tree_host_impl.cc
index f1200a6648dfae284c3b77363ad603769772aaf8..69d72a6b1c972b1c514072cf751a5a76fd9361ae 100644
--- a/components/mus/ws/window_tree_host_impl.cc
+++ b/components/mus/ws/window_tree_host_impl.cc
@@ -167,6 +167,18 @@ const mojom::ViewportMetrics& WindowTreeHostImpl::GetViewportMetrics() const {
   return display_manager_->GetViewportMetrics();
 }
 
+void WindowTreeHostImpl::SetCapture(ServerWindow* window,
+                                    bool in_nonclient_area) {
+  ServerWindow* capture_window = event_dispatcher_.capture_window();
+  if (capture_window == window)
+    return;
+  event_dispatcher_.SetCaptureWindow(window, in_nonclient_area);
+  if (window)
+    display_manager_->SetCapture();

[sky, 2016/02/08 16:57:11]

I think this is the wrong place for setting/releasing capture on the
displaymanager. In particular this doesn't cover implicit capture, which should
set/release capture too. I think the delegate should get methods for
setting/releasing capture that call to the displaymanager.

[jonross, 2016/02/10 15:57:57]

Updated EventDispatcherDelegate to have Set/ReleaseCapture.
WTHI notifies the DisplayManager in those.
EventDispatcher uses those for updating on explicit capture.

Currently DefaultDisplayManager is directly signaling the platform window of
implicit capture, without interacting with event dispatcher.

+  else
+    display_manager_->ReleaseCapture();
+}
+
 mojom::Rotation WindowTreeHostImpl::GetRotation() const {
   return display_manager_->GetRotation();
 }
@@ -399,6 +411,10 @@ void WindowTreeHostImpl::OnEvent(const ui::Event& event) {
   event_dispatcher_.ProcessEvent(std::move(mojo_event));
 }
 
+void WindowTreeHostImpl::OnLostCapture() {
+  SetCapture(nullptr, false);
+}
+
 void WindowTreeHostImpl::OnDisplayClosed() {
   if (delegate_)
     delegate_->OnDisplayClosed();
@@ -530,6 +546,11 @@ ServerWindow* WindowTreeHostImpl::GetFocusedWindowForEventDispatcher() {
   return GetFocusedWindow();
 }
 
+void WindowTreeHostImpl::OnLostCapture(ServerWindow* window) {
+  DCHECK(window);
+  connection_manager_->ProcessLostCapture(window);
+}
+
 void WindowTreeHostImpl::DispatchInputEventToWindow(ServerWindow* target,
                                                     bool in_nonclient_area,
                                                     mojom::EventPtr event) {