Bug 1230857 - Make GMPInstallManager enforce sensible permissions on GMP files at install time. r=spohl

This ensures that GMP packages with bad permissions will still be usable. For
example, a GMP without execute/read permissions in its zip won't work without
this.

--HG--
extra : rebase_source : a134fed8ef23090eafd7587df1bea73f328a21e2

toolkit/modules/GMPInstallManager.jsm

@@ -421,6 +421,9 @@ GMPExtractor.prototype = {
         }
         zipReader.extract(entry, outFile);
         extractedPaths.push(outFile.path);
+        // Ensure files are writable and executable. Otherwise we may be unable to
+        // execute or uninstall them.
+        outFile.permissions |= parseInt("0700", 8);
         log.info(entry + " was successfully extracted to: " +
             outFile.path);
       });