Convert //ash from scoped_ptr to std::unique_ptr

ash/accelerators/accelerator_interactive_uitest_chromeos.cc

Index: ash/accelerators/accelerator_interactive_uitest_chromeos.cc
diff --git a/ash/accelerators/accelerator_interactive_uitest_chromeos.cc b/ash/accelerators/accelerator_interactive_uitest_chromeos.cc
index 162ba64cc38c573efd24fdfc35703540ffdb7824..479e7eb54e4771b73c2b7435a7718f4a7b8e6524 100644
--- a/ash/accelerators/accelerator_interactive_uitest_chromeos.cc
+++ b/ash/accelerators/accelerator_interactive_uitest_chromeos.cc
@@ -168,7 +168,7 @@ TEST_F(AcceleratorInteractiveUITest, MAYBE_ChromeOsAccelerators) {
   // Test VOLUME_MUTE, VOLUME_DOWN, and VOLUME_UP.
   TestVolumeControlDelegate* volume_delegate = new TestVolumeControlDelegate;
   shell()->system_tray_delegate()->SetVolumeControlDelegate(
-      scoped_ptr<VolumeControlDelegate>(volume_delegate));
+      std::unique_ptr<VolumeControlDelegate>(volume_delegate));
   // VOLUME_MUTE.
   EXPECT_EQ(0, volume_delegate->handle_volume_mute_count());
   SendKeyPressSync(ui::VKEY_VOLUME_MUTE, false, false, false);