Add the supporting code for the cast system tray integration

chrome/browser/ui/ash/system_tray_delegate_chromeos.cc

Index: chrome/browser/ui/ash/system_tray_delegate_chromeos.cc
diff --git a/chrome/browser/ui/ash/system_tray_delegate_chromeos.cc b/chrome/browser/ui/ash/system_tray_delegate_chromeos.cc
index 28c6c481ed703c3dca1968cc2001b2f6bd169c1b..f4e1284145daa29df6ec5f3f7aee0a4f253b6661 100644
--- a/chrome/browser/ui/ash/system_tray_delegate_chromeos.cc
+++ b/chrome/browser/ui/ash/system_tray_delegate_chromeos.cc
@@ -71,6 +71,7 @@
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/supervised_user/supervised_user_service.h"
 #include "chrome/browser/supervised_user/supervised_user_service_factory.h"
+#include "chrome/browser/ui/ash/cast_config_delegate_chromeos.h"
 #include "chrome/browser/ui/ash/multi_user/multi_user_util.h"
 #include "chrome/browser/ui/ash/networking_config_delegate_chromeos.h"
 #include "chrome/browser/ui/ash/system_tray_delegate_utils.h"
@@ -195,6 +196,7 @@ SystemTrayDelegateChromeOS::SystemTrayDelegateChromeOS()
       have_session_length_limit_(false),
       should_run_bluetooth_discovery_(false),
       session_started_(false),
+      cast_config_delegate_(new CastConfigDelegateChromeos()),
       networking_config_delegate_(new NetworkingConfigDelegateChromeos()),
       volume_control_delegate_(new VolumeController()),
       device_settings_observer_(CrosSettings::Get()->AddSettingsObserver(
@@ -788,6 +790,11 @@ void SystemTrayDelegateChromeOS::ChangeProxySettings() {
   LoginDisplayHostImpl::default_host()->OpenProxySettings();
 }
 
+ash::CastConfigDelegate* SystemTrayDelegateChromeOS::GetCastConfigDelegate()
+    const {
+  return cast_config_delegate_.get();
+}
+
 ash::NetworkingConfigDelegate*
 SystemTrayDelegateChromeOS::GetNetworkingConfigDelegate() const {
   return networking_config_delegate_.get();