Remove watchers spam from log.

Remove watchers spam from log.

Not supporting file watchers is not an error. It's expected from eg. file
systems exposed via File System Provider API, especially those which are
read only.

TEST=Tested manually that watchers work and there is no spam in the log.
BUG=461735
Committed: https://crrev.com/848cef8863832443e796a9ea2deb7e4c58012e7f
Cr-Commit-Position: refs/heads/master@{#330697}

[mtomasz, 2015-05-20 01:19:44]

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

[mtomasz, 2015-05-20 01:19:53]

@yawano: PTAL. Thanks.

[yawano, 2015-05-20 02:27:18]

lgtm.

https://codereview.chromium.org/1150473002/diff/1/ui/file_manager/file_manage...
File ui/file_manager/file_manager/foreground/js/file_watcher.js (right):

https://codereview.chromium.org/1150473002/diff/1/ui/file_manager/file_manage...
ui/file_manager/file_manager/foreground/js/file_watcher.js:74: * @return
{Promise}
nit: !Promise

https://codereview.chromium.org/1150473002/diff/1/ui/file_manager/file_manage...
ui/file_manager/file_manager/foreground/js/file_watcher.js:84: * Resets the
watched entry to the passed directory. It's a best effort method.
nit: remove "to the passed directory". No directory is passed to this method.

[mtomasz, 2015-05-20 04:21:42]

https://codereview.chromium.org/1150473002/diff/1/ui/file_manager/file_manage...
File ui/file_manager/file_manager/foreground/js/file_watcher.js (right):

https://codereview.chromium.org/1150473002/diff/1/ui/file_manager/file_manage...
ui/file_manager/file_manager/foreground/js/file_watcher.js:74: * @return
{Promise}
On 2015/05/20 02:27:18, yawano wrote:
> nit: !Promise

Done.

https://codereview.chromium.org/1150473002/diff/1/ui/file_manager/file_manage...
ui/file_manager/file_manager/foreground/js/file_watcher.js:84: * Resets the
watched entry to the passed directory. It's a best effort method.
On 2015/05/20 02:27:18, yawano wrote:
> nit: remove "to the passed directory". No directory is passed to this method.

Done.

[mtomasz, 2015-05-20 04:21:50]

The CQ bit was checked by mtomasz@chromium.org

[mtomasz, 2015-05-20 04:21:51]

The patchset sent to the CQ was uploaded after l-g-t-m from yawano@chromium.org
Link to the patchset: https://codereview.chromium.org/1150473002/#ps20001
(title: "Fixed.")

[commit-bot: I haz the power, 2015-05-20 04:22:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1150473002/20001

[commit-bot: I haz the power, 2015-05-20 04:50:36]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-05-20 04:52:31]

Patchset 2 (id:??) landed as
https://crrev.com/848cef8863832443e796a9ea2deb7e4c58012e7f
Cr-Commit-Position: refs/heads/master@{#330697}