Add an option to specify requested fields for fetching metadata.

Add an option to specify requested fields for fetching metadata.

Fetching metadata is heavy, and it may cause calling stat() even though
it's not needed (is_directory is obtainable without stat()).

This CL adds the option. Backends will be updated to reflect it separately.
Also, as another step base::File::Info will be replaced with storage::Entry
or something similar with scoped_ptr's as members, to avoid reading
a member which was not requested in |fields|.

TEST=All current tests pass. But not really used yet, as backends ignore it.
BUG=558191
Committed: https://crrev.com/132dc015c1928f080ec20a132d80d751a14e25c7
Cr-Commit-Position: refs/heads/master@{#360585}

[mtomasz, 2015-11-19 03:55:52]

The CQ bit was checked by mtomasz@chromium.org to run a CQ dry run

[mtomasz, 2015-11-19 03:55:59]

Description was changed from

==========
Add an option to specify requested fields for fetching metadata.

Fetching metadata is heavy, and it may cause calling stat() even though
it's not needed (is_directory is obtainable without stat()).

This CL adds the option. Backends will be updated to reflect it separately.
Also, as another step base::File::Info will be replaced with storage::Entry
or something similar with scoped_ptr's as members, to avoid reading
a member which was not requested in |fields|.

TEST=All current tests pass. But not really used yet, as backends ignore it.
BUG=558191
==========

to

==========
Add an option to specify requested fields for fetching metadata.

Fetching metadata is heavy, and it may cause calling stat() even though
it's not needed (is_directory is obtainable without stat()).

This CL adds the option. Backends will be updated to reflect it separately.
Also, as another step base::File::Info will be replaced with storage::Entry
or something similar with scoped_ptr's as members, to avoid reading
a member which was not requested in |fields|.

TEST=All current tests pass. But not really used yet, as backends ignore it.
BUG=558191
==========

[mtomasz, 2015-11-19 03:55:59]

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

[mtomasz, 2015-11-19 03:56:08]

@tzik: PTAL. Thanks.

[commit-bot: I haz the power, 2015-11-19 03:56:17]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1455403003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1455403003/20001

[commit-bot: I haz the power, 2015-11-19 05:03:48]

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

[commit-bot: I haz the power, 2015-11-19 05:03:48]

Dry run: This issue passed the CQ dry run.

[tzik, 2015-11-19 05:20:06]

lgtm

[mtomasz, 2015-11-19 06:24:01]

The CQ bit was checked by mtomasz@chromium.org

[commit-bot: I haz the power, 2015-11-19 06:24:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1455403003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1455403003/20001

[commit-bot: I haz the power, 2015-11-19 06:35:32]

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

[commit-bot: I haz the power, 2015-11-19 06:35:33]

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

[mtomasz, 2015-11-19 06:38:48]

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

[mtomasz, 2015-11-19 06:39:12]

@kinuko: PTAL at
content/browser/renderer_host/pepper/pepper_internal_file_ref_backend.cc and
content/public/test/async_file_test_helper.cc

Thanks

[kinuko, 2015-11-19 14:52:19]

On 2015/11/19 06:39:12, mtomasz wrote:
> @kinuko: PTAL at
> content/browser/renderer_host/pepper/pepper_internal_file_ref_backend.cc and
> content/public/test/async_file_test_helper.cc
 
lgtm

[mtomasz, 2015-11-19 15:20:09]

The CQ bit was checked by mtomasz@chromium.org

[commit-bot: I haz the power, 2015-11-19 15:21:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1455403003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1455403003/20001

[commit-bot: I haz the power, 2015-11-19 15:44:16]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-11-19 15:45:21]

Patchset 2 (id:??) landed as
https://crrev.com/132dc015c1928f080ec20a132d80d751a14e25c7
Cr-Commit-Position: refs/heads/master@{#360585}