[fsp] Remove length from the OnWriteFileOperation().

[fsp] Remove length from the OnWriteFileOperation().

The length is already available as data.byteLength, where data is of
the ArrayBuffer type.

TBR=benwells@chromium.org
TEST=browser_tests, unit_tests: *FileSystemProvider*Write*
BUG=248427
Committed: https://crrev.com/3485d1a05e0cc3ad01d363cdfea6786d2368080b
Cr-Commit-Position: refs/heads/master@{#293093}

[mtomasz, 2014-09-03 04:37:35]

mtomasz@chromium.org changed reviewers:
+ fukino@chromium.org

[mtomasz, 2014-09-03 04:37:44]

@fukino: PTAL. Thanks.

[fukino, 2014-09-03 06:15:16]

On 2014/09/03 04:37:44, mtomasz wrote:
> @fukino: PTAL. Thanks.

lgtm!

[mtomasz, 2014-09-03 06:30:18]

The CQ bit was checked by mtomasz@chromium.org

[commit-bot: I haz the power, 2014-09-03 06:31:11]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/mtomasz@chromium.org/530373002/1

[mtomasz, 2014-09-03 06:43:31]

mtomasz@chromium.org changed reviewers:
+ benwells@chromium.org

[mtomasz, 2014-09-03 06:43:42]

@benwells: TBR for a trivial change in IDL.

[commit-bot: I haz the power, 2014-09-03 07:29:06]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  chromium_presubmit on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[commit-bot: I haz the power, 2014-09-03 07:35:05]

Committed patchset #1 (id:1) as 40cbc3b01c00ba196f8b689868d54a291e11a121

[commit-bot: I haz the power, 2014-09-10 03:24:16]

Patchset 1 (id:??) landed as
https://crrev.com/3485d1a05e0cc3ad01d363cdfea6786d2368080b
Cr-Commit-Position: refs/heads/master@{#293093}