Reland: mus: Enable system modal windows

components/mus/ws/window_manager_state.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/mus/ws/window_manager_state.h"
 
 #include "base/memory/weak_ptr.h"
 #include "components/mus/ws/accelerator.h"
 #include "components/mus/ws/display_manager.h"
 #include "components/mus/ws/platform_display.h"
@@ skipping 110 matching lines @@
   DCHECK(IsActive());
   if (capture_window() == window)
     return true;
   DCHECK(!window || root_->Contains(window));
   return event_dispatcher_.SetCaptureWindow(window, in_nonclient_area);
 }
 
 void WindowManagerState::ReleaseCaptureBlockedByModalWindow(
     const ServerWindow* modal_window) {
   if (!capture_window() || !modal_window->is_modal() ||
-      !modal_window->IsDrawn())
+      !modal_window->IsDrawn()) {
     return;
+  }
 
   if (modal_window->transient_parent() &&
       !modal_window->transient_parent()->Contains(capture_window())) {
     return;
   }
 
   SetCapture(nullptr, false);
 }
 
 void WindowManagerState::ReleaseCaptureBlockedByAnyModalWindow() {
-  if (!capture_window() || !capture_window()->IsBlockedByModalWindow())
+  if (!capture_window())
+    return;
+
+  bool has_system_modal =
+      system_modal_window() && system_modal_window()->IsDrawn();
+
+  if (!has_system_modal && !capture_window()->IsBlockedByModalWindow())
     return;
 
   SetCapture(nullptr, false);
 }
 
+bool WindowManagerState::SetSystemModalWindow(ServerWindow* window) {
+  DCHECK(!window->transient_parent());
+  if (system_modal_window() == window)
+    return true;
+  return event_dispatcher_.SetSystemModalWindow(window);
+}
+
 mojom::DisplayPtr WindowManagerState::ToMojomDisplay() const {
   mojom::DisplayPtr display_ptr = display_->ToMojomDisplay();
   // TODO(sky): set work area.
   display_ptr->work_area = display_ptr->bounds.Clone();
   display_ptr->frame_decoration_values = frame_decoration_values_.Clone();
   return display_ptr;
 }
 
 void WindowManagerState::OnWillDestroyTree(WindowTree* tree) {
   if (tree_awaiting_input_ack_ != tree)
@@ skipping 219 matching lines @@
 
   base::WeakPtr<Accelerator> weak_accelerator;
   if (accelerator)
     weak_accelerator = accelerator->GetWeakPtr();
   DispatchInputEventToWindowImpl(target, in_nonclient_area, event,
                                  weak_accelerator);
 }
 
 }  // namespace ws
 }  // namespace mus