Add more string_util functions to base namespace.

Add more string_util functions to base namespace.

Moves ReplaceFirstSubstringAfterOffset. It also changes the find/replace arguments to be string pieces (normally these are constants).

TBR=gauravsh@chromium.org for chromeos/network

Committed: https://crrev.com/e6dae46fc681a8ad62f6937a6ac1cab3d51938a9
Cr-Commit-Position: refs/heads/master@{#335999}

[brettw, 2015-06-23 22:02:19]

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

[sky, 2015-06-23 23:57:37]

LGTM

[brettw, 2015-06-24 16:00:39]

The CQ bit was checked by brettw@chromium.org

[commit-bot: I haz the power, 2015-06-24 16:02:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1200393002/20001

[commit-bot: I haz the power, 2015-06-24 16:13:35]

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

[commit-bot: I haz the power, 2015-06-24 16:13:42]

Try jobs failed on following builders:
  chromium_presubmit on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[brettw, 2015-06-24 17:19:45]

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

[brettw, 2015-06-24 17:20:07]

TBR gauravsh@chromium.org for chromeos/network

[brettw, 2015-06-24 17:32:33]

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

[brettw, 2015-06-24 17:32:33]

The patchset sent to the CQ was uploaded after l-g-t-m from sky@chromium.org
Link to the patchset: https://codereview.chromium.org/1200393002/#ps40001
(title: " ")

[commit-bot: I haz the power, 2015-06-24 17:33:53]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1200393002/40001

[brettw, 2015-06-24 17:38:04]

The CQ bit was unchecked by brettw@chromium.org

[brettw, 2015-06-24 17:38:10]

The CQ bit was checked by brettw@chromium.org

[commit-bot: I haz the power, 2015-06-24 17:40:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1200393002/40001

[commit-bot: I haz the power, 2015-06-24 18:21:52]

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

[commit-bot: I haz the power, 2015-06-24 18:21:54]

Exceeded global retry quota

[brettw, 2015-06-24 19:08:28]

The CQ bit was checked by brettw@chromium.org

[brettw, 2015-06-24 19:08:28]

The patchset sent to the CQ was uploaded after l-g-t-m from sky@chromium.org
Link to the patchset: https://codereview.chromium.org/1200393002/#ps60001
(title: "Android")

[commit-bot: I haz the power, 2015-06-24 19:09:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1200393002/60001

[commit-bot: I haz the power, 2015-06-24 20:54:58]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-06-24 20:56:12]

Patchset 4 (id:??) landed as
https://crrev.com/e6dae46fc681a8ad62f6937a6ac1cab3d51938a9
Cr-Commit-Position: refs/heads/master@{#335999}