[Telemetry] Rename translate_common_values + add none_value/description support

[Telemetry] Rename translate_common_values + add none_value/description support

This CL:

1. Renames translate_common_values to common_value_helpers
2. Adds none_value handling for scalars
3. Adds description handling for scalars
4. Adds unit tests for scalars.

Closes #2217. Closes #2213.

BUG=catapult:#2217,catapult:#2213
R=nednguyen

Committed: https://chromium.googlesource.com/external/github.com/catapult-project/catapult/+/cfc61b76a63ebab69d62cbc80e92c8d727f74a8f

[eakuefner, 2016-04-05 17:53:07]

PTAL.

[nednguyen, 2016-04-05 17:58:31]

The CQ bit was checked by nednguyen@google.com

[nednguyen, 2016-04-05 17:58:31]

lgtm

[commit-bot: I haz the power, 2016-04-05 17:58:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1857003003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1857003003/1

[commit-bot: I haz the power, 2016-04-05 18:18:06]

Description was changed from

==========
[Telemetry] Rename translate_common_values + add none_value/description support

This CL:

1. Renames translate_common_values to common_value_helpers
2. Adds none_value handling for scalars
3. Adds description handling for scalars
4. Adds unit tests for scalars.

Closes #2217. Closes #2213.

BUG=catapult:#2217,catapult:#2213
R=nednguyen
==========

to

==========
[Telemetry] Rename translate_common_values + add none_value/description support

This CL:

1. Renames translate_common_values to common_value_helpers
2. Adds none_value handling for scalars
3. Adds description handling for scalars
4. Adds unit tests for scalars.

Closes #2217. Closes #2213.

BUG=catapult:#2217,catapult:#2213
R=nednguyen

Committed:
https://chromium.googlesource.com/external/github.com/catapult-project/catapu...
==========

[commit-bot: I haz the power, 2016-04-05 18:18:07]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/external/github.com/catapult-project/catapu...