Pull test utilities from MinidumpMemoryWriter’s test out into their own file

Pull test utilities from MinidumpMemoryWriter’s test out into their own file.

These utilities are also useful to MinidumpThreadWriter’s test.

TEST=minidump_test MinidumpMemoryWriter.*
R=rsesek@chromium.org

Committed: https://chromium.googlesource.com/crashpad/crashpad/+/9c76cc60db794ded66a219aad8ad1dac8307e860

[Mark Mentovai, 2014-10-07 19:01:55]

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

[Mark Mentovai, 2014-10-07 19:01:56]

https://codereview.chromium.org/639513002/diff/1/minidump/minidump_memory_wri...
File minidump/minidump_memory_writer_test_util.cc (right):

https://codereview.chromium.org/639513002/diff/1/minidump/minidump_memory_wri...
minidump/minidump_memory_writer_test_util.cc:75: if (expected->Memory.Rva != 0)
{
This new conditional is the only change to the code. The MinidumpThreadWriter
test doesn’t compute the expected offsets (RVAs) of the memory data.

[Robert Sesek, 2014-10-07 21:39:05]

LGTM

[Mark Mentovai, 2014-10-07 21:58:47]

Committed patchset #1 (id:1) manually as
9c76cc60db794ded66a219aad8ad1dac8307e860 (presubmit successful).