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

chrome/browser/chrome_browser_application_mac.mm

Index: chrome/browser/chrome_browser_application_mac.mm
diff --git a/chrome/browser/chrome_browser_application_mac.mm b/chrome/browser/chrome_browser_application_mac.mm
index 2889a64c9674e552fd5fcb685112a8188a468d25..fba6506e18c705463b0ea837569f180d9af6d768 100644
--- a/chrome/browser/chrome_browser_application_mac.mm
+++ b/chrome/browser/chrome_browser_application_mac.mm
@@ -406,7 +406,7 @@ void SwizzleInit() {
   }
 
   // Minimize the window by keeping this close to the super call.
-  scoped_ptr<base::mac::ScopedNSExceptionEnabler> enabler(NULL);
+  scoped_ptr<base::mac::ScopedNSExceptionEnabler> enabler;
   if (enableNSExceptions)
     enabler.reset(new base::mac::ScopedNSExceptionEnabler());
   return [super sendAction:anAction to:aTarget from:sender];