Implement and test aura::client::CaptureClient in views::NativeWidgetMus for plumbing (Set|Release)…

ui/views/mus/platform_window_mus.cc

Index: ui/views/mus/platform_window_mus.cc
diff --git a/ui/views/mus/platform_window_mus.cc b/ui/views/mus/platform_window_mus.cc
index d9dc54b07596ae10def61afe98cb8a070492fb0a..bacc15d22b65f3d306e822e028cf5b282422d779 100644
--- a/ui/views/mus/platform_window_mus.cc
+++ b/ui/views/mus/platform_window_mus.cc
@@ -76,13 +76,9 @@ void PlatformWindowMus::SetTitle(const base::string16& title) {
   NOTIMPLEMENTED();
 }
 
-void PlatformWindowMus::SetCapture() {
-  mus_window_->SetCapture();
-}
+void PlatformWindowMus::SetCapture() {}
 
-void PlatformWindowMus::ReleaseCapture() {
-  mus_window_->ReleaseCapture();
-}
+void PlatformWindowMus::ReleaseCapture() {}
 
 void PlatformWindowMus::ToggleFullscreen() {
   NOTIMPLEMENTED();