Use mojo SystemTray interfaces for both mash and classic ash

ash/common/system/tray/system_tray_controller.cc

Index: ash/common/system/tray/system_tray_controller.cc
diff --git a/ash/common/system/tray/system_tray_controller.cc b/ash/common/system/tray/system_tray_controller.cc
new file mode 100644
index 0000000000000000000000000000000000000000..54c0216714face4f773f7518364f9b8a759e085a
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+++ b/ash/common/system/tray/system_tray_controller.cc
@@ -0,0 +1,65 @@
+// 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 "ash/common/system/tray/system_tray_controller.h"
+
+#include "ash/common/system/tray/system_tray_notifier.h"
+#include "ash/common/wm_shell.h"
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "services/shell/public/cpp/connector.h"
+
+namespace ash {
+
+SystemTrayController::SystemTrayController(shell::Connector* connector)
+    : connector_(connector), hour_clock_type_(base::GetHourClockType()) {}
+
+SystemTrayController::~SystemTrayController() {}
+
+void SystemTrayController::ShowDateSettings() {
+  if (ConnectToSystemTrayClient())
+    system_tray_client_->ShowDateSettings();
+}
+
+void SystemTrayController::BindRequest(mojom::SystemTrayRequest request) {
+  bindings_.AddBinding(this, std::move(request));
+}
+
+bool SystemTrayController::ConnectToSystemTrayClient() {
+  // Unit tests may not have a connector.
+  if (!connector_)
+    return false;
+
+#if defined(OS_CHROMEOS)
+  // If already connected, nothing to do.
+  if (system_tray_client_.is_bound())
+    return true;
+
+  // Connect (or reconnect) to the interface.
+  if (WmShell::Get()->IsRunningInMash())
+    connector_->ConnectToInterface("exe:chrome", &system_tray_client_);
+  else
+    connector_->ConnectToInterface("exe:content_browser", &system_tray_client_);
+
+  // Handle chrome crashes by forcing a reconnect on the next request.
+  system_tray_client_.set_connection_error_handler(base::Bind(
+      &SystemTrayController::OnClientConnectionError, base::Unretained(this)));
+  return true;
+#else
+  // The SystemTrayClient interface in the browser is only implemented for
+  // Chrome OS, so don't try to connect on other platforms.
+  return false;
+#endif  // defined(OS_CHROMEOS)
+}
+
+void SystemTrayController::OnClientConnectionError() {
+  system_tray_client_.reset();
+}
+
+void SystemTrayController::SetUse24HourClock(bool use_24_hour) {
+  hour_clock_type_ = use_24_hour ? base::k24HourClock : base::k12HourClock;
+  WmShell::Get()->system_tray_notifier()->NotifyDateFormatChanged();
+}
+
+}  // namespace ash