mash: Change CastConfigDelegate to a mojoified CastConfigClient.

ash/test/tray_cast_test_api.cc

Index: ash/test/tray_cast_test_api.cc
diff --git a/ash/test/tray_cast_test_api.cc b/ash/test/tray_cast_test_api.cc
index 2aabdc0bc4ff3e4d00f5a05ea73de3878424c758..a105bf3d1783ab4df25bd526b51d322f0a957111 100644
--- a/ash/test/tray_cast_test_api.cc
+++ b/ash/test/tray_cast_test_api.cc
@@ -4,7 +4,6 @@
 
 #include "ash/test/tray_cast_test_api.h"
 
-#include "ash/common/cast_config_delegate.h"
 #include "ash/common/system/tray/system_tray.h"
 #include "ash/common/system/tray/system_tray_delegate.h"
 #include "ash/common/wm_shell.h"
@@ -48,15 +47,6 @@ void TrayCastTestAPI::OnCastingSessionStartedOrStopped(bool is_casting) {
   tray_cast_->OnCastingSessionStartedOrStopped(is_casting);
 }
 
-void TrayCastTestAPI::ReleaseConfigCallbacks() {
-  if (WmShell::Get() && WmShell::Get()->system_tray_delegate()) {
-    WmShell::Get()
-        ->system_tray_delegate()
-        ->GetCastConfigDelegate()
-        ->RemoveObserver(tray_cast_);
-  }
-}
-
 bool TrayCastTestAPI::IsViewDrawn(TrayCast::ChildViewId id) const {
   const views::View* view = tray_cast_->GetDefaultView()->GetViewByID(id);
   return view != nullptr && view->IsDrawn();