The old implementation doesn't handle possible overflows,
when year is too large, for example. It makes a result
to be larger than 2^63 - 1, which results in overflow.

Fix Posix: use safe_math.h for multiplication and addition. If
overflow occurs, return possibly maximum platform dependent
value.

Fix Mac and Win: if safe cast is impossible, return Time(0).

Fix media and components: use day of week as well, as long
as unused variable results in undefined behavior and overflow

BUG=653445

Review-Url: https://codereview.chromium.org/2405453002
Cr-Commit-Position: refs/heads/master@{#427064}