Instead of passing {uint8_t*, size_t} pairs as arguments, pass
{Vector<uint8_t>}. This is less error prone and {Vector} provides some
helpful methods.

R=ahaas@chromium.org

Bug: v8:7754
Change-Id: I7469054774618e0bd5c9d38501759b1b2c51d104
Reviewed-on: https://chromium-review.googlesource.com/1134773Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54406}