Split 'CookieOptions' out into a .h/.cc file.

I need to add a member to CookieOptions in order to support First-Party
Only cookies, but doing so makes CookieOptions' constructor "complex".
Splitting that work out into a separate patch for clarity.

BUG=459154

Review URL: https://codereview.chromium.org/1258023002

Cr-Commit-Position: refs/heads/master@{#340657}
3 files changed