Clean-up the code for default variations in chrome://flags.

Clean-up the code for default variations in chrome://flags.

The CL 2129543002 introduced an option to override variation parameters
using a feature in chrome://flags. The list of options for the given
feature always includes "Default", "Enabled", and "Disabled". Even
though the semantics of "Enabled" was meant as 'enabled with the default
parameter values', the API forced to specify the variation for "Enabled"
as well.

This is unnecessarily cumbersome and confusing. This CL makes the
"Enabled" option completely automatic - no need to specify its variation
any more.

BUG=609059
Committed: https://crrev.com/05f7ce3363a189c35495863316bb8c1aed91b8c8
Cr-Commit-Position: refs/heads/master@{#405190}

[jkrcal, 2016-07-13 13:59:05]

The CQ bit was checked by jkrcal@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-07-13 13:59:17]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[jkrcal, 2016-07-13 14:00:48]

jkrcal@chromium.org changed reviewers:
+ asvitkine@chromium.org

[jkrcal, 2016-07-13 14:00:49]

Alexei, PTAL.

(This is my last CL to you in the current sequence, I promise :)

[Alexei Svitkine (slow), 2016-07-13 14:07:13]

lgtm

https://codereview.chromium.org/2146903002/diff/1/components/flags_ui/feature...
File components/flags_ui/feature_entry.cc (right):

https://codereview.chromium.org/2146903002/diff/1/components/flags_ui/feature...
components/flags_ui/feature_entry.cc:46: // First two options do not correspond
to variations.
Nit: I would actually rephrase this slightly, i.e. "do not have variations
params."

[jkrcal, 2016-07-13 15:02:24]

The CQ bit was checked by jkrcal@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-07-13 15:02:40]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-07-13 16:28:16]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-07-13 16:28:17]

Dry run: This issue passed the CQ dry run.

[jkrcal, 2016-07-13 16:36:15]

The CQ bit was checked by jkrcal@chromium.org

[jkrcal, 2016-07-13 16:36:15]

The patchset sent to the CQ was uploaded after l-g-t-m from
asvitkine@chromium.org
Link to the patchset: https://codereview.chromium.org/2146903002/#ps60001
(title: "iOS test crash fix? #2")

[commit-bot: I haz the power, 2016-07-13 16:36:59]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-07-13 16:42:26]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2016-07-13 16:42:43]

CQ bit was unchecked.

[commit-bot: I haz the power, 2016-07-13 16:44:17]

Description was changed from

==========
Clean-up the code for default variations in chrome://flags.

The CL 2129543002 introduced an option to override variation parameters
using a feature in chrome://flags. The list of options for the given
feature always includes "Default", "Enabled", and "Disabled". Even
though the semantics of "Enabled" was meant as 'enabled with the default
parameter values', the API forced to specify the variation for "Enabled"
as well.

This is unnecessarily cumbersome and confusing. This CL makes the
"Enabled" option completely automatic - no need to specify its variation
any more.

BUG=609059
==========

to

==========
Clean-up the code for default variations in chrome://flags.

The CL 2129543002 introduced an option to override variation parameters
using a feature in chrome://flags. The list of options for the given
feature always includes "Default", "Enabled", and "Disabled". Even
though the semantics of "Enabled" was meant as 'enabled with the default
parameter values', the API forced to specify the variation for "Enabled"
as well.

This is unnecessarily cumbersome and confusing. This CL makes the
"Enabled" option completely automatic - no need to specify its variation
any more.

BUG=609059

Committed: https://crrev.com/05f7ce3363a189c35495863316bb8c1aed91b8c8
Cr-Commit-Position: refs/heads/master@{#405190}
==========

[commit-bot: I haz the power, 2016-07-13 16:44:18]

Patchset 4 (id:??) landed as
https://crrev.com/05f7ce3363a189c35495863316bb8c1aed91b8c8
Cr-Commit-Position: refs/heads/master@{#405190}