ui: Cleanup class/struct forward declarations

content/shell/utility/shell_content_utility_client.cc

Index: content/shell/utility/shell_content_utility_client.cc
diff --git a/content/shell/utility/shell_content_utility_client.cc b/content/shell/utility/shell_content_utility_client.cc
index faa732ba753eb48aa5a7ecc810c65b1ded280e82..195976d758af53dfb12b002d58916ca9c5f34764 100644
--- a/content/shell/utility/shell_content_utility_client.cc
+++ b/content/shell/utility/shell_content_utility_client.cc
@@ -66,8 +66,7 @@ class TestServiceImpl : public mojom::TestService {
   DISALLOW_COPY_AND_ASSIGN(TestServiceImpl);
 };
 
-std::unique_ptr<service_manager::Service> CreateTestService(
-    const base::Closure& quit_closure) {
+std::unique_ptr<service_manager::Service> CreateTestService() {
   return std::unique_ptr<service_manager::Service>(new TestService);
 }