Revert of Revert of Drive: Let DriveUploader use batch request API.

Revert of Revert of Drive: Let DriveUploader use batch request API. (patchset #1 id:1 of https://codereview.chromium.org/1135353004/)

Reason for revert:
The failure is not caused by the patch. MigrationSingleClientTest.AllTypesIndividually looks flaky.

Original issue's description:
> Revert of Drive: Let DriveUploader use batch request API. (patchset #7 id:120001 of https://codereview.chromium.org/1134633003/)
>
> Reason for revert:
> MigrationSingleClientTest.AllTypesIndividually is broken by this change on Linux GN:
>
> http://build.chromium.org/p/chromium.linux/builders/Linux%20GN/builds/28327
>
> Original issue's description:
> > Drive: Let DriveUploader use batch request API.
> >
> > The CL lets DriveUploader use batch request API. DriveUploader does asynchronous
> > preparation before calling API on service interface. To hold batch request
> > during the asynchronous preparation, the CL introduce refcounted hepler class,
> > which manages life time of batch request configurator.
> >
> > BUG=451917
> > TEST=DriveUploaderTest
> >
> > Committed: https://crrev.com/9cf453b74c8790f6d7a91f958ec998a9fa5a1fa0
> > Cr-Commit-Position: refs/heads/master@{#329599}
>
> TBR=kinaba@chromium.org,tzik@chromium.org,hirono@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=451917
>
> Committed: https://crrev.com/e244812ae9a09d001f24f9aaaf780c80f976d790
> Cr-Commit-Position: refs/heads/master@{#329610}

TBR=kinaba@chromium.org,tzik@chromium.org,sergeyv@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=451917
Committed: https://crrev.com/09b621eaa36477b9b157bbb12fc83865fc6da4bc
Cr-Commit-Position: refs/heads/master@{#329613}

[hirono, 2015-05-13 10:18:28]

Created Revert of Revert of Drive: Let DriveUploader use batch request API.

[commit-bot: I haz the power, 2015-05-13 10:18:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1138883004/1

[commit-bot: I haz the power, 2015-05-13 10:19:34]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-13 10:20:21]

Patchset 1 (id:??) landed as
https://crrev.com/09b621eaa36477b9b157bbb12fc83865fc6da4bc
Cr-Commit-Position: refs/heads/master@{#329613}