Remove dependency to file_system_operation_impl.h from chrome/

Remove dependency to file_system_operation_impl.h outside from chrome/

Instead introducing a static FileSystemOperation::Create method.

As a preparation for moving fileapi code from webkit/ to content/.
(file_system_operation.h will be placed under content/public/browser/ while
file_system_operation_impl.{h,cc} will be placed under content/browser/fileapi
and will be hidden from chrome/)

BUG=265770
TEST=existing tests

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=221976

[kinuko, 2013-09-06 10:33:16]

Mechanical cleanup only. PTL

c/b/chromeos/fileapi: satorux
c/b/media_galleries/fileapi: vandebo
everything else: nhiroki

[vandebo (ex-Chrome), 2013-09-06 15:24:14]

*media* LGTM

[satorux1, 2013-09-09 01:12:17]

chrome/browser/chromeos/fileapi/file_system_backend.cc lgtm

[nhiroki, 2013-09-09 01:16:55]

lgtm

[commit-bot: I haz the power, 2013-09-09 02:16:11]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/kinuko@chromium.org/23835005/1

[commit-bot: I haz the power, 2013-09-09 06:15:26]

Change committed as 221976