Reusing base::StringPairs in src/extentions/

Reusing base::StringPairs in src/extentions/

Reusing the "base::StringPairs" insted of  "std::vector<std::pair<std::string, std::string> >"
same is defined in  base/strings/string_split.h.

BUG=412250
Committed: https://crrev.com/9d13b52bb61f2bf496fac4caf76f43e5c02c6a3c
Cr-Commit-Position: refs/heads/master@{#296192}

[ARUNKK, 2014-09-23 12:55:49]

kulkarni.a@samsung.com changed reviewers:
+ finnur@chromium.org

[ARUNKK, 2014-09-23 12:55:49]

PTAL

[Finnur, 2014-09-23 14:27:28]

LGTM

[ARUNKK, 2014-09-23 14:48:01]

The CQ bit was checked by kulkarni.a@samsung.com

[commit-bot: I haz the power, 2014-09-23 14:49:04]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/591313004/1

[commit-bot: I haz the power, 2014-09-23 15:36:32]

Committed patchset #1 (id:1) as 701b3d6ee3aedabc7ae3654d74abfd34be3b49ff

[commit-bot: I haz the power, 2014-09-23 15:37:18]

Patchset 1 (id:??) landed as
https://crrev.com/9d13b52bb61f2bf496fac4caf76f43e5c02c6a3c
Cr-Commit-Position: refs/heads/master@{#296192}