Add a minimal --undefok to SkCommandLineFlags.

Add a minimal --undefok to SkCommandLineFlags.

Similar in spirit to gflags' undefok, I'd like to be able to ignore
specific unknown flags.  This lets me run the same command line on, say,
a branch that's got a new flag and on a clean branch tracking
origin/master.  This is handy for performance comparison, etc.

It's not essential, and if you hate this I can find another way.

As an example, I want to compare the runtime of SKP recording with my new code.  I've added a flag --skr to bench_record to help this.  So I want to compare

origin/master: out/Release/bench_record
my patch:      out/Release/bench_record --skr

This lets me run both as out/Release/bench_record --undefok skr --skr, which is handy for scripts and things.

BUG=skia:

Committed: http://code.google.com/p/skia/source/detail?r=13945

[scroggo, 2014-03-25 20:04:23]

On 2014/03/25 19:59:48, mtklein wrote:

LGTM

[mtklein, 2014-03-25 20:05:20]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2014-03-25 20:05:23]

CQ is trying da patch. Follow status at
https://skia-tree-status.appspot.com/cq/mtklein@chromium.org/209393015/1

[scroggo, 2014-03-25 20:09:06]

https://codereview.chromium.org/209393015/diff/1/tools/flags/SkCommandLineFla...
File tools/flags/SkCommandLineFlags.cpp (right):

https://codereview.chromium.org/209393015/diff/1/tools/flags/SkCommandLineFla...
tools/flags/SkCommandLineFlags.cpp:11: DEFINE_string(undefok, "", "Silently
ignore unknown flags listed here instead of crashing.");
Maybe specify that the use of this flag must follow undefok?

[commit-bot: I haz the power, 2014-03-25 21:00:04]

Change committed as 13945