Add string_number_conversion and its test

Add string_number_conversion and its test.

This includes the StringToNumber() function, both int and unsigned int variants.

Similar functionality is available in base, but it is unsuitable for
applications where a number’s base may be determined based on an "0x" or
"0X" prefix (hexadecimal) or an "0" prefix (octal).

TEST=util_test StringNumberConversion.*
R=rsesek@chromium.org

Committed: https://chromium.googlesource.com/crashpad/crashpad/+/10d1b76b90b23463c22bf8d06a3f93781e48d2e2

[Mark Mentovai, 2014-09-09 20:50:05]

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

[Robert Sesek, 2014-09-10 16:56:54]

LGTM

https://codereview.chromium.org/557033002/diff/1/util/stdlib/string_number_co...
File util/stdlib/string_number_conversion_test.cc (right):

https://codereview.chromium.org/557033002/diff/1/util/stdlib/string_number_co...
util/stdlib/string_number_conversion_test.cc:35: {"2147483647", true,
std::numeric_limits<int>::max()},
This is going to fail on your ILP64 SPARC build...

[Mark Mentovai, 2014-09-10 19:29:45]

We’ll deal. :)

[Mark Mentovai, 2014-09-10 19:30:19]

Committed patchset #1 (id:1) manually as 10d1b76 (presubmit successful).