Fix compilation error Dart_Initialize has a new parameter

TBR=fschneider@google.com,alanknight@google.com

Review URL: https://codereview.chromium.org/1698383002 .

git-svn-id: https://src.chromium.org/blink/branches/dart/2454_1@202778 bbb929c8-8fbe-4397-9dbb-9b2b20218538
1 file changed