Use base::StringPairs where appropriate from /components

Becuase base/strings/string_split.h defines:
typedef std::vector<std::pair<std::string, std::string> > StringPairs;
And use iterator to iterate stl::vector element.

BUG=412250
Committed: https://crrev.com/1af96aa7b7d721bad77b818166892fd413716e98
Cr-Commit-Position: refs/heads/master@{#294832}

[limasdf, 2014-09-14 04:24:11]

limasdf@gmail.com changed reviewers:
+ boliu@chromium.org, isherman@chromium.org, mathp@chromium.org

[limasdf, 2014-09-14 04:24:12]

Please take a look.

boliu for auto_login_parser.
isherman for autofill.
mathp for leveldb_proto.

[Ilya Sherman, 2014-09-15 02:45:29]

autofill lgtm

[Mathieu, 2014-09-15 13:38:32]

lgtm

[boliu, 2014-09-15 14:51:38]

lgtm

[limasdf, 2014-09-15 15:02:23]

The CQ bit was checked by limasdf@gmail.com

[commit-bot: I haz the power, 2014-09-15 15:03:21]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/545193008/1

[commit-bot: I haz the power, 2014-09-15 16:09:39]

Committed patchset #1 (id:1) as d6c9923fae4c173452e7eb475c709d73a1856afb

[commit-bot: I haz the power, 2014-09-15 16:19:20]

Patchset 1 (id:??) landed as
https://crrev.com/1af96aa7b7d721bad77b818166892fd413716e98
Cr-Commit-Position: refs/heads/master@{#294832}