Fix type bustage in cocoa view. Not part of build.

embedding/browser/cocoa/src/nsCocoaBrowserService.mm

@@ -43,7 +43,7 @@
 #include "NSBrowserView.h"
 #include "nsCRT.h"
 
-PRInt32 nsCocoaBrowserService::sNumBrowsers = 0;
+PRUint32 nsCocoaBrowserService::sNumBrowsers = 0;
 nsAlertController* nsCocoaBrowserService::sController = nsnull;
 nsCocoaBrowserService* nsCocoaBrowserService::sSingleton = nsnull;