[App Banner] Use appropriate type parameters for WebCallbacks.

chrome/renderer/banners/app_banner_client.cc

Index: chrome/renderer/banners/app_banner_client.cc
diff --git a/chrome/renderer/banners/app_banner_client.cc b/chrome/renderer/banners/app_banner_client.cc
index 28a9b67ae8507d287cac3068901d60fe852f6bae..215fa29026b0b26c401c519a7daea831ca3b8e72 100644
--- a/chrome/renderer/banners/app_banner_client.cc
+++ b/chrome/renderer/banners/app_banner_client.cc
@@ -53,11 +53,8 @@ void AppBannerClient::ResolveEvent(
   if (!callbacks)
     return;
 
-  scoped_ptr<blink::WebAppBannerPromptResult> result(
-      new blink::WebAppBannerPromptResult(
-        blink::WebString::fromUTF8(platform),
-        outcome));
-  callbacks->onSuccess(result.release());
+  callbacks->onSuccess(blink::WebAppBannerPromptResult(
+      blink::WebString::fromUTF8(platform), outcome));
   banner_callbacks_.Remove(request_id);
 }