Mozilla Central about:home Session Restore Button

[sarracini]

Split from #1974. The about:home tab has a launcher with the following features: Downloads, Bookmarks, History, Add-ons, Sync, Preferences and Session Restore. Needs UX specs

Strings (with plural form):

• Restore {num} tab(s) from your last session

[AmyYLee]

There is a bug filed for the session restore feature here along with attached UX specs. https://bugzilla.mozilla.org/show_bug.cgi?id=1352068

[andreicristianpetcu]

so just restore session, no Preferences :( I really like the preferences and the Firefox logo link in about:home.

[sarracini]

After chatting with @bryanbell, we're no longer doing the "launcher" that has all those options at the bottom of about:home. We are still doing session restore, so let's repurpose this bug for just the session restore implementation. Bryan said he'll drop some specs in this bug