Add support code to test the cast system tray item.

ash/test/tray_cast_test_api.cc

+// Copyright 2015 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 "ash/test/tray_cast_test_api.h"
+
+namespace ash {
+
+TrayCastTestAPI::TrayCastTestAPI(TrayCast* tray_cast) : tray_cast_(tray_cast) {
+}
+
+TrayCastTestAPI::~TrayCastTestAPI() {
+}
+
+bool TrayCastTestAPI::IsTrayInitializedForTest() const {
+  return tray_cast_->default_ != nullptr;
+}
+
+bool TrayCastTestAPI::IsTrayVisibleForTest() const {
+  return tray_cast_->default_ != nullptr && tray_cast_->default_->IsDrawn();
+}
+
+bool TrayCastTestAPI::IsTrayCastViewVisibleForTest() const {
+  return tray_cast_->default_ != nullptr &&
+         tray_cast_->default_->ActiveChildView() ==
+             tray_cast_->default_->cast_view();

[oshima, 2015/07/17 22:59:28]

easy way to test this is to define IDs for view in TrayCast, assign them to
views (View::set_id), then find the view using GetViewByID. This way, you don't
have to expose internal classes. 

For IsTrayVisibleForTest. you can just get view by id and check IsDrawn()

[jdufault, 2015/07/18 00:55:42]

Done.

+}
+
+bool TrayCastTestAPI::IsTraySelectViewVisibleForTest() const {
+  return tray_cast_->default_ != nullptr &&
+         tray_cast_->default_->ActiveChildView() ==
+             tray_cast_->default_->select_view();
+}
+
+void TrayCastTestAPI::StartCastForTest(const std::string& receiver_id) {
+  if (tray_cast_->detailed_ != nullptr)
+    tray_cast_->detailed_->SimulateViewClickedForTest(receiver_id);
+}
+
+void TrayCastTestAPI::StopCastForTest() {
+  tray_cast_->default_->cast_view()->StopCasting();

[oshima, 2015/07/17 22:59:28]

and you can have these two methods on TrayCast.

[jdufault, 2015/07/18 00:55:42]

Done.

+}
+
+void TrayCastTestAPI::OnCastingSessionStartedOrStopped(bool is_casting) {
+  tray_cast_->OnCastingSessionStartedOrStopped(is_casting);
+}
+
+}  // namespace ash