Cleanup: Pass std::string as const reference from components/

Cleanup: Pass std::string as const reference from components/

Passing std::string by reference can prevent extra copying of object.

BUG=367418
TEST=
R=blundell@chromium.org,jochen@chromium.org,sdefresne@chromium.org

Committed: https://crrev.com/939799a4b72e978038109fce97bf043b988428b4
Cr-Commit-Position: refs/heads/master@{#351023}

[vabr (Chromium), 2015-09-21 06:46:22]

vabr@chromium.org changed reviewers:
+ vabr@chromium.org

[vabr (Chromium), 2015-09-21 06:46:23]

components/password_manager/core/browser/login_database_unittest.cc LGTM

[sdefresne, 2015-09-21 07:17:30]

lgtm

[ki.stfu, 2015-09-21 07:47:55]

The CQ bit was checked by ki.stfu@gmail.com

[commit-bot: I haz the power, 2015-09-21 07:47:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1355983002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1355983002/1

[commit-bot: I haz the power, 2015-09-21 07:56:03]

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

[commit-bot: I haz the power, 2015-09-21 07:56:04]

Try jobs failed on following builders:
  linux_chromium_compile_dbg_32_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[jochen (gone - plz use gerrit), 2015-09-21 15:02:27]

please ensure that you have green trybots before sending large refactoring CLs
out for review

[blundell, 2015-09-21 15:12:11]

On 2015/09/21 15:02:27, jochen wrote:
> please ensure that you have green trybots before sending large refactoring CLs
> out for review

(that's a pretty good general rule, really)

[ki.stfu, 2015-09-21 18:41:18]

On 2015/09/21 15:12:11, blundell wrote:
> On 2015/09/21 15:02:27, jochen wrote:
> > please ensure that you have green trybots before sending large refactoring
CLs
> > out for review
> 
> (that's a pretty good general rule, really)

Is there a way to do this? My computer is very slow (~10h for full rebuild) and
"git cl try" gives me the following error:
```
$ git cl try
ERROR: Error in response. Code: 403. Reason: . Message: Forbidden.
```

[ki.stfu, 2015-09-21 18:46:35]

On 2015/09/21 18:41:18, ki.stfu wrote:
> On 2015/09/21 15:12:11, blundell wrote:
> > On 2015/09/21 15:02:27, jochen wrote:
> > > please ensure that you have green trybots before sending large refactoring
> CLs
> > > out for review
> > 
> > (that's a pretty good general rule, really)
> 
> Is there a way to do this? My computer is very slow (~10h for full rebuild)
and
> "git cl try" gives me the following error:
> ```
> $ git cl try
> ERROR: Error in response. Code: 403. Reason: . Message: Forbidden.
> ```

P.S. this CL depends on https://codereview.chromium.org/1354373002/

[ki.stfu, 2015-09-24 18:48:46]

The CQ bit was checked by ki.stfu@gmail.com to run a CQ dry run

[commit-bot: I haz the power, 2015-09-24 18:50:34]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1355983002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1355983002/40001

[commit-bot: I haz the power, 2015-09-24 19:08:58]

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

[commit-bot: I haz the power, 2015-09-24 19:08:59]

Dry run: Try jobs failed on following builders:
  android_clang_dbg_recipe on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/android_clang_d...)
  android_compile_dbg on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/android_compile...)
  cast_shell_linux on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/cast_shell_linu...)
  linux_chromium_gn_chromeos_rel on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  ios_rel_device_ninja on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_rel_device_ni...)

[ki.stfu, 2015-09-28 03:34:17]

The CQ bit was checked by ki.stfu@gmail.com

[ki.stfu, 2015-09-28 03:34:17]

The patchset sent to the CQ was uploaded after l-g-t-m from vabr@chromium.org,
sdefresne@chromium.org
Link to the patchset: https://codereview.chromium.org/1355983002/#ps80001
(title: "Revert to PS2")

[commit-bot: I haz the power, 2015-09-28 03:34:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1355983002/80001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1355983002/80001

[commit-bot: I haz the power, 2015-09-28 04:41:28]

Committed patchset #5 (id:80001)

[commit-bot: I haz the power, 2015-09-28 04:42:15]

Patchset 5 (id:??) landed as
https://crrev.com/939799a4b72e978038109fce97bf043b988428b4
Cr-Commit-Position: refs/heads/master@{#351023}