[Merge-m58] Revert of Extensions: Only create Web request rules registry if Declarative Web Request…

[Merge-m58] Revert of Extensions: Only create Web request rules registry if Declarative Web Request is enabled. (patchset #4 id:60001 of https://codereview.chromium.org/2705513002/ )

Reason for revert:
Declarative Web Request is enabled on Stable through <webview>. Hence we can't disable creation of rules registry on Stable.

Original issue's description:
> Extensions: Only create Web request rules registry if Declarative Web Request is enabled.
>
> Currently the Web Request rules registry required by the Declarative Web
> Request API is created on all Chrome channels, even though the Declarative Web
> Request API is disabled on Stable. The UMA metric
> Extensions.NetworkDelayRegistryLoad shows significant delay for some web
> requests which are blocked due to the loading of the Web Request rules
> registry even on Stable. The mean delay is around 1.7 sec and the median delay
> is around 50ms.
>
> This CL modifies RulesRegistryService::EnsureDefaultRulesRegistriesRegistered
> to ensure the Web Request rules registry is only created for the channels on
> which the Declarative Web Request API is enabled. To do this,
> Feature::IsAvailableToChannel is introduced.
>
> BUG=693243
>
> Review-Url: https://codereview.chromium.org/2705513002
> Cr-Commit-Position: refs/heads/master@{#452240}
> Committed: https://chromium.googlesource.com/chromium/src/+/a77b53baca5f2a4ff102592c17c8ea3f53dd5307

BUG=693243
Review-Url: https://codereview.chromium.org/2773593003
Cr-Commit-Position: refs/heads/master@{#459269}
(cherry picked from commit 9df2cccc337ca57188f9709b2205439347870606)

Review-Url: https://codereview.chromium.org/2783543003 .
Cr-Commit-Position: refs/branch-heads/3029@{#462}
Cr-Branched-From: 939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed: https://chromium.googlesource.com/chromium/src/+/96768d9da47097e7cbc5162a24bbe636ad6223f5

[karandeepb, 2017-03-28 22:43:01]

Description was changed from

==========
[Merge-m58] Revert of Extensions: Only create Web request rules registry if
Declarative Web Request is enabled. (patchset #4 id:60001 of
https://codereview.chromium.org/2705513002/ )

Reason for revert:
Declarative Web Request is enabled on Stable through <webview>. Hence we can't
disable creation of rules registry on Stable.

Original issue's description:
> Extensions: Only create Web request rules registry if Declarative Web Request
is enabled.
>
> Currently the Web Request rules registry required by the Declarative Web
> Request API is created on all Chrome channels, even though the Declarative Web
> Request API is disabled on Stable. The UMA metric
> Extensions.NetworkDelayRegistryLoad shows significant delay for some web
> requests which are blocked due to the loading of the Web Request rules
> registry even on Stable. The mean delay is around 1.7 sec and the median delay
> is around 50ms.
>
> This CL modifies RulesRegistryService::EnsureDefaultRulesRegistriesRegistered
> to ensure the Web Request rules registry is only created for the channels on
> which the Declarative Web Request API is enabled. To do this,
> Feature::IsAvailableToChannel is introduced.
>
> BUG=693243
>
> Review-Url: https://codereview.chromium.org/2705513002
> Cr-Commit-Position: refs/heads/master@{#452240}
> Committed:
https://chromium.googlesource.com/chromium/src/+/a77b53baca5f2a4ff102592c17c8...

BUG=693243

Review-Url: https://codereview.chromium.org/2773593003
Cr-Commit-Position: refs/heads/master@{#459269}
(cherry picked from commit 9df2cccc337ca57188f9709b2205439347870606)
==========

to

==========
[Merge-m58] Revert of Extensions: Only create Web request rules registry if
Declarative Web Request is enabled. (patchset #4 id:60001 of
https://codereview.chromium.org/2705513002/ )

Reason for revert:
Declarative Web Request is enabled on Stable through <webview>. Hence we can't
disable creation of rules registry on Stable.

Original issue's description:
> Extensions: Only create Web request rules registry if Declarative Web Request
is enabled.
>
> Currently the Web Request rules registry required by the Declarative Web
> Request API is created on all Chrome channels, even though the Declarative Web
> Request API is disabled on Stable. The UMA metric
> Extensions.NetworkDelayRegistryLoad shows significant delay for some web
> requests which are blocked due to the loading of the Web Request rules
> registry even on Stable. The mean delay is around 1.7 sec and the median delay
> is around 50ms.
>
> This CL modifies RulesRegistryService::EnsureDefaultRulesRegistriesRegistered
> to ensure the Web Request rules registry is only created for the channels on
> which the Declarative Web Request API is enabled. To do this,
> Feature::IsAvailableToChannel is introduced.
>
> BUG=693243
>
> Review-Url: https://codereview.chromium.org/2705513002
> Cr-Commit-Position: refs/heads/master@{#452240}
> Committed:
https://chromium.googlesource.com/chromium/src/+/a77b53baca5f2a4ff102592c17c8...

BUG=693243

Review-Url: https://codereview.chromium.org/2773593003
Cr-Commit-Position: refs/heads/master@{#459269}
(cherry picked from commit 9df2cccc337ca57188f9709b2205439347870606)

Review-Url: https://codereview.chromium.org/2783543003 .
Cr-Commit-Position: refs/branch-heads/3029@{#462}
Cr-Branched-From:
939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed:
https://chromium.googlesource.com/chromium/src/+/96768d9da47097e7cbc5162a24bb...
==========

[karandeepb, 2017-03-28 22:43:02]

Committed patchset #1 (id:1) manually as
96768d9da47097e7cbc5162a24bbe636ad6223f5.