Use NewScriptState in ImageBitmapFactories

This CL replaces ScriptState in ImageBitmapFactories with NewScriptState.

BUG=357144

Review URL: https://codereview.chromium.org/225283017

git-svn-id: svn://svn.chromium.org/blink/trunk@171044 bbb929c8-8fbe-4397-9dbb-9b2b20218538