Fix caca backend build.

ui/ozone/platform/caca/ozone_platform_caca.cc

Index: ui/ozone/platform/caca/ozone_platform_caca.cc
diff --git a/ui/ozone/platform/caca/ozone_platform_caca.cc b/ui/ozone/platform/caca/ozone_platform_caca.cc
index fa2d21422251ffc79bf1bd061329f36e6867ca81..9f7873e4060ea6e148cf073d8d30c47a3827e09c 100644
--- a/ui/ozone/platform/caca/ozone_platform_caca.cc
+++ b/ui/ozone/platform/caca/ozone_platform_caca.cc
@@ -57,7 +57,7 @@ class OzonePlatformCaca : public OzonePlatform {
         delegate, window_manager_.get(), event_source_.get(), bounds));
     if (!caca_window->Initialize())
       return nullptr;
-    return caca_window;
+    return std::move(caca_window);
   }
   scoped_ptr<NativeDisplayDelegate> CreateNativeDisplayDelegate() override {
     return make_scoped_ptr(new NativeDisplayDelegateOzone());