I opted to leave casts to types that were definitely the same size
alone. reinterpret_cast<uintptr_t>(pointer) and
reinterpret_cast<intptr_t>(pointer) should always be safe, for example.
Casts to other integral types have been replaced with
FromPointerCast<>(), which does zero-extension or sign-extension based
on the target type.
To make it possible to use FromPointerCast<>() with some use sites that
were already using checked_cast<>(), FromPointerCast<>() now uses
check_cast<>() when converting to a narrower type.
Test: crashpad_util_test FromPointerCast*, others
Change-Id: I4a71b4aa2d87f545c75524290a702f5f3138d675
Reviewed-on: https://chromium-review.googlesource.com/489701
Reviewed-by: Scott Graham <scottmg@chromium.org>
