Move yet more from WmShell to Shell

ash/test/shell_test_api.cc

Index: ash/test/shell_test_api.cc
diff --git a/ash/test/shell_test_api.cc b/ash/test/shell_test_api.cc
index eea718cb6fef33cfed5e65e5dc8161d964937f5d..c81507e26303d5a0f5fd06eb416ea33b27435d38 100644
--- a/ash/test/shell_test_api.cc
+++ b/ash/test/shell_test_api.cc
@@ -3,8 +3,10 @@
 // found in the LICENSE file.
 
 #include "ash/test/shell_test_api.h"
+
 #include "ash/common/palette_delegate.h"
 #include "ash/common/session/session_state_delegate.h"
+#include "ash/common/shelf/shelf_delegate.h"
 #include "ash/root_window_controller.h"
 #include "ash/shell.h"
 
@@ -45,5 +47,10 @@ void ShellTestApi::SetSessionStateDelegate(
   shell_->session_state_delegate_.reset(session_state_delegate);
 }
 
+void ShellTestApi::SetShelfDelegate(
+    std::unique_ptr<ShelfDelegate> test_delegate) {
+  shell_->shelf_delegate_ = std::move(test_delegate);
+}
+
 }  // namespace test
 }  // namespace ash