wm: Update namespace and header define guards.

src/platform/window_manager/stacking_manager_test.cc

Index: src/platform/window_manager/stacking_manager_test.cc
diff --git a/src/platform/window_manager/stacking_manager_test.cc b/src/platform/window_manager/stacking_manager_test.cc
index c20d77bba5a95a11a9b7dc228d64d40e46a7d5e7..24b7f197c33d614a71e70f90fa465f404372415b 100644
--- a/src/platform/window_manager/stacking_manager_test.cc
+++ b/src/platform/window_manager/stacking_manager_test.cc
@@ -18,7 +18,7 @@
 DEFINE_bool(logtostderr, false,
             "Print debugging messages to stderr (suppressed otherwise)");
 
-namespace chromeos {
+namespace window_manager {
 
 class StackingManagerTest : public BasicWindowManagerTest {
  protected:
@@ -120,8 +120,8 @@ TEST_F(StackingManagerTest, StackWindowAtTopOfLayer) {
             stage->GetStackingIndex(win2.shadow()->group()));
 }
 
-}  // namespace chromeos
+}  // namespace window_manager
 
 int main(int argc, char** argv) {
-  return chromeos::InitAndRunTests(&argc, argv, &FLAGS_logtostderr);
+  return window_manager::InitAndRunTests(&argc, argv, &FLAGS_logtostderr);
 }