Use of base::StringPairs appropriately in base

Use of base::StringPairs appropriately in base

Using  base::StringPairs in base folder
Becuase base/strings/string_split.h defines:
typedef std::vector<std::pair<std::string, std::string> > StringPairs;

BUG=412250
Committed: https://crrev.com/f42513a7b8925d77c487033821b12fcce04ef554
Cr-Commit-Position: refs/heads/master@{#296647}

[MRV, 2014-09-25 03:36:35]

mohan.reddy@samsung.com changed reviewers:
+ thakis@chromium.org

[MRV, 2014-09-25 03:36:36]

PTAL

[Nico, 2014-09-25 03:48:05]

lgtm

[MRV, 2014-09-25 03:53:48]

On 2014/09/25 03:48:05, Nico (hiding) wrote:
> lgtm

Thanks Mr.Nico for LGTM

[MRV, 2014-09-25 03:53:52]

The CQ bit was checked by mohan.reddy@samsung.com

[commit-bot: I haz the power, 2014-09-25 03:54:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/605613003/1

[commit-bot: I haz the power, 2014-09-25 04:45:32]

Committed patchset #1 (id:1) as 44d0e159f18a7652fbd036b0a9e8f1cc9e24bfe6

[commit-bot: I haz the power, 2014-09-25 04:46:12]

Patchset 1 (id:??) landed as
https://crrev.com/f42513a7b8925d77c487033821b12fcce04ef554
Cr-Commit-Position: refs/heads/master@{#296647}