Add uint128_struct and its test

Add uint128_struct and its test.

This will be used in the upcoming Minidump context structures.

This also updates mini_chromium to ba9b15f1b6a7 to pick up:

ba9b15f1b6a7 Make bit_cast available in C++11 mode.

R=rsesek@chromium.org

Committed: https://chromium.googlesource.com/crashpad/crashpad/+/fee5d8aea971a1c8e5415afd5510f966ed0404d6

[Mark Mentovai, 2014-09-22 18:51:54]

mark@chromium.org changed reviewers:
+ rsesek@chromium.org

[Robert Sesek, 2014-09-22 19:02:14]

LGTM

https://codereview.chromium.org/583283003/diff/1/util/numeric/int128_test.cc
File util/numeric/int128_test.cc (right):

https://codereview.chromium.org/583283003/diff/1/util/numeric/int128_test.cc#...
util/numeric/int128_test.cc:34: COMPILE_ASSERT(sizeof(uint128) ==
sizeof(kBytes), sizes_must_be_equal);
Maybe also something simpler: COMPILE_ASSERT(8 * sizeof(uint128) == 128).

[Mark Mentovai, 2014-09-22 19:41:20]

https://codereview.chromium.org/583283003/diff/1/util/numeric/int128_test.cc
File util/numeric/int128_test.cc (right):

https://codereview.chromium.org/583283003/diff/1/util/numeric/int128_test.cc#...
util/numeric/int128_test.cc:34: COMPILE_ASSERT(sizeof(uint128) ==
sizeof(kBytes), sizes_must_be_equal);
rsesek wrote:
> Maybe also something simpler: COMPILE_ASSERT(8 * sizeof(uint128) == 128).

Well, I’m testing that it’s safe to bit_cast between the two, so I wanted to
have both variables in the expression.

[Mark Mentovai, 2014-09-22 19:46:05]

Committed patchset #1 (id:1) manually as fee5d8a (presubmit successful).

[Robert Sesek, 2014-09-22 19:46:12]

https://codereview.chromium.org/583283003/diff/1/util/numeric/int128_test.cc
File util/numeric/int128_test.cc (right):

https://codereview.chromium.org/583283003/diff/1/util/numeric/int128_test.cc#...
util/numeric/int128_test.cc:34: COMPILE_ASSERT(sizeof(uint128) ==
sizeof(kBytes), sizes_must_be_equal);
On 2014/09/22 19:41:20, Mark Mentovai wrote:
> rsesek wrote:
> > Maybe also something simpler: COMPILE_ASSERT(8 * sizeof(uint128) == 128).
> 
> Well, I’m testing that it’s safe to bit_cast between the two, so I wanted to
> have both variables in the expression.

I meant "in addition to".