Change the signature of SetScreenshotDelegate() to show ownership transfer more clearly.

ash/accelerators/accelerator_controller_unittest.cc

Index: ash/accelerators/accelerator_controller_unittest.cc
diff --git a/ash/accelerators/accelerator_controller_unittest.cc b/ash/accelerators/accelerator_controller_unittest.cc
index 9f86b45738ccf1a88618350a60dfe76d2ba9ac63..1de432f5cff489de4a9d4d281cfc2559873a6569 100644
--- a/ash/accelerators/accelerator_controller_unittest.cc
+++ b/ash/accelerators/accelerator_controller_unittest.cc
@@ -279,7 +279,8 @@ TEST_F(AcceleratorControllerTest, GlobalAccelerators) {
     EXPECT_TRUE(GetController()->Process(
         ui::Accelerator(ui::VKEY_PRINT, false, false, false)));
     DummyScreenshotDelegate* delegate = new DummyScreenshotDelegate;
-    GetController()->SetScreenshotDelegate(delegate);
+    GetController()->SetScreenshotDelegate(
+        scoped_ptr<ScreenshotDelegate>(delegate).Pass());
     EXPECT_EQ(0, delegate->handle_take_screenshot_count());
     EXPECT_TRUE(GetController()->Process(
         ui::Accelerator(ui::VKEY_F5, false, true, false)));