[Telemetry] Updates record_wpr to use argparse.

[Telemetry] Updates record_wpr to use argparse.

This patch updates record_wpr to use argparse for:
+ record_wpr <XYZ> will make <XYZ> a benchmark name to be recorded.
+ record_wpr --user-story <XYZ> will make <XYZ> a user
story (page set) name to be recorded
+ record_wpr --list-benchmarks & --list-user-stories will
list out benchmark names & user stories (page sets) names.
This is useful since the current record_wpr target name
matching is a bit funky due to  discover.DiscoverClasses's
keys naming scheme.

Subsequent patches will update it so that the target
matching name for benchmarks matched the convention in
benchmark_runner.py & matching name for user stories use
the user stories's class name.

Since more code refactoring are required, I haven't added
unittest for these new changes yet.

TEST="
git cl patch this.
./perf/record_wpr --help
./perf/record_wpr --list-user-stories
./perf/record_wpr --list-bechmarks

"

BUG=470865
Committed: https://crrev.com/0272cae5fa1c70ec751fd5dd19b31a368babc0c8
Cr-Commit-Position: refs/heads/master@{#330206}

[nednguyen, 2015-05-15 18:49:51]

nednguyen@google.com changed reviewers:
+ sullivan@chromium.org

[nednguyen, 2015-05-15 18:53:41]

Patchset #1 (id:1) has been deleted

[sullivan, 2015-05-15 19:19:42]

lgtm

https://codereview.chromium.org/1147533004/diff/20001/tools/telemetry/telemet...
File tools/telemetry/telemetry/record_wpr.py (right):

https://codereview.chromium.org/1147533004/diff/20001/tools/telemetry/telemet...
tools/telemetry/telemetry/record_wpr.py:102: output_stream.write('Available page
sets\' names:\n')
Why "page sets" and not "user stories"? If we want our users to use new
terminology, we should have it messaged to them, right?

I also forgot to follow up: did we decide to rename UserStory->Story?

[nednguyen, 2015-05-15 19:58:16]

https://codereview.chromium.org/1147533004/diff/20001/tools/telemetry/telemet...
File tools/telemetry/telemetry/record_wpr.py (right):

https://codereview.chromium.org/1147533004/diff/20001/tools/telemetry/telemet...
tools/telemetry/telemetry/record_wpr.py:102: output_stream.write('Available page
sets\' names:\n')
On 2015/05/15 19:19:41, sullivan wrote:
> Why "page sets" and not "user stories"? If we want our users to use new
> terminology, we should have it messaged to them, right?
> 
> I also forgot to follow up: did we decide to rename UserStory->Story?

I put page sets because we only list out page_set (line 105 & TODO)

[nednguyen, 2015-05-15 20:11:31]

On 2015/05/15 19:58:16, nednguyen (slow review) wrote:
>
https://codereview.chromium.org/1147533004/diff/20001/tools/telemetry/telemet...
> File tools/telemetry/telemetry/record_wpr.py (right):
> 
>
https://codereview.chromium.org/1147533004/diff/20001/tools/telemetry/telemet...
> tools/telemetry/telemetry/record_wpr.py:102: output_stream.write('Available
page
> sets\' names:\n')
> On 2015/05/15 19:19:41, sullivan wrote:
> > Why "page sets" and not "user stories"? If we want our users to use new
> > terminology, we should have it messaged to them, right?
> > 
> > I also forgot to follow up: did we decide to rename UserStory->Story?
> 
> I put page sets because we only list out page_set (line 105 & TODO)

Updated the name user-story -> story. Update the code so that it passes extra
args to WprRecorder, PTAL again

[sullivan, 2015-05-15 20:13:11]

lgtm

[nednguyen, 2015-05-15 20:23:29]

The CQ bit was checked by nednguyen@google.com

[commit-bot: I haz the power, 2015-05-15 20:25:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1147533004/40001

[commit-bot: I haz the power, 2015-05-15 21:52:40]

Committed patchset #2 (id:40001)

[commit-bot: I haz the power, 2015-05-18 11:27:57]

Patchset 2 (id:??) landed as
https://crrev.com/0272cae5fa1c70ec751fd5dd19b31a368babc0c8
Cr-Commit-Position: refs/heads/master@{#330206}