Fix compile error with clang and use_aura=1

apps/shell/browser/shell_desktop_controller.cc

Index: apps/shell/browser/shell_desktop_controller.cc
diff --git a/apps/shell/browser/shell_desktop_controller.cc b/apps/shell/browser/shell_desktop_controller.cc
index 0aa4b1157ddd4820105f3d5db713c794a4d96721..37ed8e38753d3132fd303dcc62d4541ce6780888 100644
--- a/apps/shell/browser/shell_desktop_controller.cc
+++ b/apps/shell/browser/shell_desktop_controller.cc
@@ -75,7 +75,7 @@ aura::WindowTreeHost* ShellDesktopController::GetWindowTreeHost() {
 
 #if defined(OS_CHROMEOS) && defined(USE_X11)
 void ShellDesktopController::OnDisplayModeChanged(
-    const std::vector<ui::OutputConfigurator::DisplayState>& outputs) OVERRIDE {
+    const std::vector<ui::OutputConfigurator::DisplayState>& outputs) {
   gfx::Size size = GetPrimaryDisplaySize();
   if (!size.IsEmpty())
     wm_test_helper_->host()->UpdateRootWindowSize(size);