Rewrite scoped_ptr<T>(NULL) to use the default ctor in content/.

content/browser/browser_plugin/browser_plugin_host_browsertest.cc

Index: content/browser/browser_plugin/browser_plugin_host_browsertest.cc
diff --git a/content/browser/browser_plugin/browser_plugin_host_browsertest.cc b/content/browser/browser_plugin/browser_plugin_host_browsertest.cc
index 852719fea693c221fc9b44519aa6a6e338017500..ea6cae48ed14ace245d0fd64817086672457dd16 100644
--- a/content/browser/browser_plugin/browser_plugin_host_browsertest.cc
+++ b/content/browser/browser_plugin/browser_plugin_host_browsertest.cc
@@ -857,7 +857,7 @@ scoped_ptr<net::test_server::HttpResponse> EmptyResponseHandler(
         new EmptyHttpResponse);
   }
 
-  return scoped_ptr<net::test_server::HttpResponse>(NULL);
+  return scoped_ptr<net::test_server::HttpResponse>();
 }
 
 // Handles |request| by serving a redirect response.
@@ -866,7 +866,7 @@ scoped_ptr<net::test_server::HttpResponse> RedirectResponseHandler(
     const GURL& redirect_target,
     const net::test_server::HttpRequest& request) {
   if (!StartsWithASCII(path, request.relative_url, true))
-    return scoped_ptr<net::test_server::HttpResponse>(NULL);
+    return scoped_ptr<net::test_server::HttpResponse>();
 
   scoped_ptr<net::test_server::BasicHttpResponse> http_response(
       new net::test_server::BasicHttpResponse);