win: Add UUID::InitializeFromSystemUUID()

win: Add UUID::InitializeFromSystemUUID().

The new call is also used in
CrashReportDatabaseWin::PrepareNewCrashReport(). Previously, that method
used the UUID::InitializeFromBytes() constructor. That actually caused
various fields of the UUID to be byte-swapped so that the ::UUID and
crashpad::UUID would be different UUIDs. Although a UUID is mostly
random, the version field in data_3 is used as a namespace and should be
4 for random UUIDs, and this was not the case under swapping.

TEST=crashpad_util_test UUID.FromSystem
BUG=crashpad:1
R=scottmg@chromium.org

Committed: https://chromium.googlesource.com/crashpad/crashpad/+/e7b80a52f5b9832814485b58f66d4b13117a5186

[Mark Mentovai, 2015-03-13 16:43:38]

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

[scottmg, 2015-03-13 16:52:32]

lgtm

https://codereview.chromium.org/1004913004/diff/20001/util/misc/uuid_test.cc
File util/misc/uuid_test.cc (right):

https://codereview.chromium.org/1004913004/diff/20001/util/misc/uuid_test.cc#...
util/misc/uuid_test.cc:234: EXPECT_EQ(system_string_utf8, uuid.ToString());
maybe just system_string == uuid.ToString16()? Or does that not work because of
the silly string16s?

[Mark Mentovai, 2015-03-13 17:00:16]

That works, still needs reinterpret_cast<>. Updated.

[scottmg, 2015-03-13 17:41:22]

still lgtm

[Mark Mentovai, 2015-03-13 17:53:42]

Committed patchset #4 (id:60001) manually as
e7b80a52f5b9832814485b58f66d4b13117a5186 (presubmit successful).