Convert //extensions/browser/api from scoped_ptr to std::unique_ptr

extensions/browser/api/serial/serial_event_dispatcher.h

Index: extensions/browser/api/serial/serial_event_dispatcher.h
diff --git a/extensions/browser/api/serial/serial_event_dispatcher.h b/extensions/browser/api/serial/serial_event_dispatcher.h
index 10188af493aefe4180b0b051937d763cf5e38c51..70588ca035336188b9f933409a13f496adb9d2da 100644
--- a/extensions/browser/api/serial/serial_event_dispatcher.h
+++ b/extensions/browser/api/serial/serial_event_dispatcher.h
@@ -65,11 +65,11 @@ class SerialEventDispatcher : public BrowserContextKeyedAPI {
                               serial::ReceiveError error);
 
   static void PostEvent(const ReceiveParams& params,
-                        scoped_ptr<extensions::Event> event);
+                        std::unique_ptr<extensions::Event> event);
 
   static void DispatchEvent(void* browser_context_id,
                             const std::string& extension_id,
-                            scoped_ptr<extensions::Event> event);
+                            std::unique_ptr<extensions::Event> event);
 
   content::BrowserThread::ID thread_id_;
   content::BrowserContext* const context_;