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

chrome/browser/chrome_browser_main_extra_parts_aura.cc

Index: chrome/browser/chrome_browser_main_extra_parts_aura.cc
diff --git a/chrome/browser/chrome_browser_main_extra_parts_aura.cc b/chrome/browser/chrome_browser_main_extra_parts_aura.cc
index fca681202023a2618f3e10bc32196a27729cbae6..ec2da9b312d752804c3b4a6f5b0a57e967f91876 100644
--- a/chrome/browser/chrome_browser_main_extra_parts_aura.cc
+++ b/chrome/browser/chrome_browser_main_extra_parts_aura.cc
@@ -43,8 +43,8 @@ void ChromeBrowserMainExtraPartsAura::PreProfileInit() {
 
   // Shell takes ownership of ChromeShellDelegate.
   ash::Shell* shell = ash::Shell::CreateInstance(new ChromeShellDelegate);
-  // AcceleratorController takes ownership of ScreenshotDelegate.
-  shell->accelerator_controller()->SetScreenshotDelegate(new ScreenshotTaker);
+  shell->accelerator_controller()->SetScreenshotDelegate(
+      scoped_ptr<ash::ScreenshotDelegate>(new ScreenshotTaker).Pass());
 
   // Make sure the singleton ScreenOrientationListener object is created.
   ScreenOrientationListener::GetInstance();