Introduce ash mojo interface for lock screen action handlers

ash/action_handler/action_handler_state_controller.cc

Index: ash/action_handler/action_handler_state_controller.cc
diff --git a/ash/action_handler/action_handler_state_controller.cc b/ash/action_handler/action_handler_state_controller.cc
new file mode 100644
index 0000000000000000000000000000000000000000..118dc0dea827cf1c460987c98667e7f485be68c6
--- /dev/null
+++ b/ash/action_handler/action_handler_state_controller.cc
@@ -0,0 +1,87 @@
+// Copyright 2017 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/action_handler/action_handler_state_controller.h"
+
+#include <utility>
+
+#include "base/logging.h"
+
+namespace ash {
+
+ActionHandlerStateController::ActionHandlerStateController() {}
+
+ActionHandlerStateController::~ActionHandlerStateController() {}
+
+void ActionHandlerStateController::AddObserver(
+    ActionHandlerStateObserver* observer) {
+  observers_.AddObserver(observer);
+}
+
+void ActionHandlerStateController::RemoveObserver(
+    ActionHandlerStateObserver* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+void ActionHandlerStateController::BindRequest(
+    mojom::ActionHandlerStateControllerRequest request) {
+  bindings_.AddBinding(this, std::move(request));
+}
+
+mojom::ActionHandlerState ActionHandlerStateController::GetState(
+    mojom::ActionHandlerAction action) {
+  DCHECK_EQ(mojom::ActionHandlerAction::kNewNote, action);
+
+  if (!action_handler_)
+    return mojom::ActionHandlerState::kNotSupported;
+  return new_note_state_;
+}
+
+void ActionHandlerStateController::SetActionHandler(
+    mojom::ActionHandlerPtr action_handler) {
+  mojom::ActionHandlerState old_effective_new_note_state =
+      GetState(mojom::ActionHandlerAction::kNewNote);
+
+  action_handler_ = std::move(action_handler);
+
+  // Setting action handler value can change effective state - notify observers
+  // if that was the case.
+  if (GetState(mojom::ActionHandlerAction::kNewNote) !=
+      old_effective_new_note_state) {
+    NotifyActionStateChanged(mojom::ActionHandlerAction::kNewNote);
+  }
+}
+
+void ActionHandlerStateController::UpdateActionState(
+    mojom::ActionHandlerAction action,
+    mojom::ActionHandlerState state) {
+  if (action != mojom::ActionHandlerAction::kNewNote) {
+    LOG(ERROR) << "Unexpected action " << action;
+    return;
+  }
+
+  if (state == new_note_state_)
+    return;
+
+  new_note_state_ = state;
+
+  if (action_handler_)
+    NotifyActionStateChanged(action);
+}
+
+void ActionHandlerStateController::RequestHandleAction(
+    mojom::ActionHandlerAction action) {
+  if (!action_handler_)
+    return;
+
+  action_handler_->RequestHandleAction(action);
+}
+
+void ActionHandlerStateController::NotifyActionStateChanged(
+    mojom::ActionHandlerAction action) {
+  for (auto& observer : observers_)
+    observer.OnActionStateChanged(action, GetState(action));
+}
+
+}  // namespace ash