DevTools: Trigger PRESUBMIT when injected scripts are modified.

R=dpranke@chromium.org, lushnikov@chromium.org, vsevik@chromium.org

Review URL: https://chromiumcodereview.appspot.com/18620006

git-svn-id: svn://svn.chromium.org/blink/trunk@154340 bbb929c8-8fbe-4397-9dbb-9b2b20218538