Clarify the documentation for url::{AddStandardScheme,IsStandard}.

Clarify the documentation for url::{AddStandardScheme,IsStandard}.

And GURL::IsStandard, which calls url::IsStandard.

BUG=487399
TBR=abarth

Committed: https://crrev.com/29ae548c923ccd5f4c61ab1609006bed1a34ee4f
Cr-Commit-Position: refs/heads/master@{#330495}

[palmer, 2015-05-16 00:04:51]

palmer@chromium.org changed reviewers:
+ brettw@chromium.org

[brettw, 2015-05-16 00:12:15]

LGTM

[palmer, 2015-05-19 02:40:47]

The CQ bit was checked by palmer@chromium.org

[palmer, 2015-05-19 02:40:48]

The patchset sent to the CQ was uploaded after l-g-t-m from brettw@chromium.org
Link to the patchset: https://codereview.chromium.org/1139923005/#ps20001
(title: "Tighten the definition by referring to RFC 3986.")

[commit-bot: I haz the power, 2015-05-19 02:41:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1139923005/20001

[commit-bot: I haz the power, 2015-05-19 08:43:45]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-05-19 08:44:43]

Patchset 2 (id:??) landed as
https://crrev.com/29ae548c923ccd5f4c61ab1609006bed1a34ee4f
Cr-Commit-Position: refs/heads/master@{#330495}