Rename shell namespace to service_manager

ash/mus/window_manager_unittest.cc

Index: ash/mus/window_manager_unittest.cc
diff --git a/ash/mus/window_manager_unittest.cc b/ash/mus/window_manager_unittest.cc
index d4075534c09059c2516f67948a8f1a8c28914a4b..7ffe427f81668063e555843579a023d8c1e79e0a 100644
--- a/ash/mus/window_manager_unittest.cc
+++ b/ash/mus/window_manager_unittest.cc
@@ -31,9 +31,10 @@ class WindowTreeClientDelegate : public ui::WindowTreeClientDelegate {
   DISALLOW_COPY_AND_ASSIGN(WindowTreeClientDelegate);
 };
 
-class WindowManagerTest : public shell::test::ServiceTest {
+class WindowManagerTest : public service_manager::test::ServiceTest {
  public:
-  WindowManagerTest() : shell::test::ServiceTest("exe:mash_unittests") {}
+  WindowManagerTest()
+      : service_manager::test::ServiceTest("exe:mash_unittests") {}
   ~WindowManagerTest() override {}
 
  private: