Reland: mus: Enable system modal windows

components/mus/ws/test_utils.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/test_utils.h"
 
 #include "base/memory/ptr_util.h"
 #include "cc/output/copy_output_request.h"
 #include "components/mus/surfaces/surfaces_state.h"
 #include "components/mus/ws/display_binding.h"
@@ skipping 104 matching lines @@
   tree_->SetEventObserver(std::move(matcher), event_observer_id);
 }
 
 // DisplayTestApi  ------------------------------------------------------------
 
 DisplayTestApi::DisplayTestApi(Display* display) : display_(display) {}
 DisplayTestApi::~DisplayTestApi() {}
 
 // EventDispatcherTestApi  ----------------------------------------------------
 
+bool EventDispatcherTestApi::IsWindowPointerTarget(
+    const ServerWindow* window) const {
+  for (const auto& pair : ed_->pointer_targets_) {
+    if (pair.second.window == window)
+      return true;
+  }
+  return false;
+}
+
 int EventDispatcherTestApi::NumberPointerTargetsForWindow(
     ServerWindow* window) {
   int count = 0;
   for (const auto& pair : ed_->pointer_targets_)
     if (pair.second.window == window)
       count++;
   return count;
 }
 
 // TestDisplayBinding ---------------------------------------------------------
@@ skipping 246 matching lines @@
     return nullptr;
   if (!tree->AddWindow(parent_client_id, client_window_id))
     return nullptr;
   *client_id = client_window_id;
   return tree->GetWindowByClientId(client_window_id);
 }
 
 }  // namespace test
 }  // namespace ws
 }  // namespace mus