Merge "Skip signature checking preinstalled WebViews."

    private static boolean providerHasValidSignature(WebViewProviderInfo provider,

            PackageInfo packageInfo, SystemInterface systemInterface) {

        if (systemInterface.systemIsDebuggable()) {

            return true;

        }

        // If no signature is declared, instead check whether the package is included in the

        // system.

        if (provider.signatures == null || provider.signatures.length == 0) {

            return packageInfo.applicationInfo.isSystemApp();

        }

        // Skip checking signatures on debuggable builds, for development purposes.

        if (systemInterface.systemIsDebuggable()) return true;

        // Allow system apps to be valid providers regardless of signature.

        if (packageInfo.applicationInfo.isSystemApp()) return true;

        // We don't support packages with multiple signatures.

        if (packageInfo.signatures.length != 1) return false;

        // Return whether the package signature matches any of the valid signatures

        // If any of the declared signatures match the package signature, it's valid.

        for (Signature signature : provider.signatures) {

            if (signature.equals(packageInfo.signatures[0])) return true;

        }

        return false;

    }