Change some snapshot- or temporary-file related changes to use ScopedFile

Change some snapshot- or temporary-file related changes to use ScopedFile

- Remove FileSnapshotPolicy, and change
  FileSystemFileUtil::CreateSnapshotFile() to return webkit_blob::ScopedFile
  (if implementors want the backend to control the snapshot file's lifetime).
  This allows implementors to set arbitrary callbacks and
 also reduces the possibility of snapshot file leakage.

- Change DriveFileSyncService's temporary file handling to use
  webkit_blob::ScopedFile to simplify the codebase & reduce the
  possibility of temporary file leakage.

BUG=162598
TEST=existing tests

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=196640

[michaeln, 2013-04-22 21:09:34]

thnx for the preview of callsites

[kinuko, 2013-04-24 04:42:08]

This one's ready for review too. (Patch based on
https://codereview.chromium.org/14261015/)
Can you take a look?

[kinuko, 2013-04-24 14:16:28]

+gbillock (and cc-ing tommycli) as this patch changes AsyncFileUtil interface
for CreateSnapshotFile.  Greg/Tommy, can you take a quick look at following
files to see if the change and documentation look reasonable?  (I'll rebase the
patch before I land)

webkit/fileapi/async_file_util.h
webkit/fileapi/device_media_async_file_util.*

Thanks!

[tzik, 2013-04-25 05:06:07]

lgtm

https://codereview.chromium.org/14075016/diff/18001/chrome/browser/sync_file_...
File chrome/browser/sync_file_system/drive_file_sync_service.cc (right):

https://codereview.chromium.org/14075016/diff/18001/chrome/browser/sync_file_...
chrome/browser/sync_file_system/drive_file_sync_service.cc:68:
BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE));
Since this function should be called on IO-allowed thread, can it be
MessageLoopProxy::current()?

https://codereview.chromium.org/14075016/diff/18001/webkit/fileapi/media/devi...
File webkit/fileapi/media/device_media_async_file_util.h (right):

https://codereview.chromium.org/14075016/diff/18001/webkit/fileapi/media/devi...
webkit/fileapi/media/device_media_async_file_util.h:16: class
SequencedTaskRunner;
sort?

[kinuko, 2013-04-25 06:02:08]

https://codereview.chromium.org/14075016/diff/18001/chrome/browser/sync_file_...
File chrome/browser/sync_file_system/drive_file_sync_service.cc (right):

https://codereview.chromium.org/14075016/diff/18001/chrome/browser/sync_file_...
chrome/browser/sync_file_system/drive_file_sync_service.cc:68:
BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE));
On 2013/04/25 05:06:07, tzik wrote:
> Since this function should be called on IO-allowed thread, can it be
> MessageLoopProxy::current()?

Done.

https://codereview.chromium.org/14075016/diff/18001/webkit/fileapi/media/devi...
File webkit/fileapi/media/device_media_async_file_util.h (right):

https://codereview.chromium.org/14075016/diff/18001/webkit/fileapi/media/devi...
webkit/fileapi/media/device_media_async_file_util.h:16: class
SequencedTaskRunner;
On 2013/04/25 05:06:07, tzik wrote:
> sort?

Done.

[kinuko, 2013-04-25 06:06:29]

+vandebo

Steve, mind doing an owner's review for the changes under
chrome/browser/media_galleries/fileapi/ ?

(Greg, I also tried to improve documentation in async_file_util.h in the new
patch)

[vandebo (ex-Chrome), 2013-04-25 17:37:08]

chrome/browser/media_galleries/fileapi/ LGTM

On 2013/04/25 06:06:29, kinuko wrote:
> +vandebo
> 
> Steve, mind doing an owner's review for the changes under
> chrome/browser/media_galleries/fileapi/ ?
> 
> (Greg, I also tried to improve documentation in async_file_util.h in the new
> patch)

[commit-bot: I haz the power, 2013-04-26 04:56:16]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/kinuko@chromium.org/14075016/44001

[kinuko, 2013-04-26 07:13:33]

Committed patchset #5 manually as r196640 (presubmit successful).