Small extra validations on permission checks: reject "0" as a valid permission

content/browser/child_process_security_policy_impl.cc

Index: content/browser/child_process_security_policy_impl.cc
===================================================================
--- content/browser/child_process_security_policy_impl.cc	(revision 174890)
+++ content/browser/child_process_security_policy_impl.cc	(working copy)
@@ -146,6 +146,8 @@
 
   // Determine if the certain permissions have been granted to a file.
   bool HasPermissionsForFile(const FilePath& file, int permissions) {
+    if (!permissions || file.empty() || !file.IsAbsolute())
+      return false;
     FilePath current_path = file.StripTrailingSeparators();
     FilePath last_path;
     int skip = 0;