Performance/Frontend

Gavin:

• bug 699854 - Refactor Downloads APIs to use async Storage [Q3]
• bug 699850 - Refactor all synchronous history APIs to use async Storage APIs [some in Q3]
• bug 899401 - Reduce thumbnailing overhead [Q3?]

Dolske:

• bug 355063 - Password manager does not work on script-generated forms - Q3

Taras:

• bug 853388 + bug 853389 - JSON+Async addon manager - Early Q3
• bug 838577 - Async session-store - Q3(looks like Q4 due to new 'e10s' design)