Upgrade Blink to milliseconds-based last modified filetimes, part 4.

Upgrade Blink to milliseconds-based last modified filetimes, part 4.

Have content::FileInfoToWebFileInfo() set the temporarily Blink-unused
field WebFileInfo::modificationTime to something milliseconds-based

Once landed, this is to allow Blink to switch to no longer using
WebFileInfo::modificationTimeMS, but modificationTime only (again.)

This is the fourth patch in the following series,

1: [blink] add WebFileInfo::modificationTimeMS [ https://codereview.chromium.org/873723004/ ]
2: [chromium] fill in modificationTimeMS [ https://codereview.chromium.org/884413002/ ]
3: [blink] make use of modificationTimeMS [ https://codereview.chromium.org/884393002/ ]
4: [chromium] *this one* [ https://codereview.chromium.org/862203003/ ]
5: [blink] switch to using modificationTime instead of *MS [ https://codereview.chromium.org/882343002/ ]
6: [chromium] stop setting modificationTimeMS [ https://codereview.chromium.org/890523002/ ]
7: [blink] remove modificationTimeMS [ https://codereview.chromium.org/869613005/ ]

R=jochen
BUG=451747
Committed: https://crrev.com/08b24b4f9ea7ad41a31347da059a35fb4ad592b3
Cr-Commit-Position: refs/heads/master@{#315322}

[sof, 2015-02-08 22:14:13]

sigbjornf@opera.com changed reviewers:
+ jam@chromium.org, jochen@chromium.org

[sof, 2015-02-08 22:14:14]

Please take a look.

Nearing the end here, honest :)

[jochen (gone - plz use gerrit), 2015-02-09 14:20:55]

lgtm

[sof, 2015-02-09 15:21:29]

The CQ bit was checked by sigbjornf@opera.com

[commit-bot: I haz the power, 2015-02-09 15:22:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/862203003/1

[commit-bot: I haz the power, 2015-02-09 16:45:58]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-09 16:46:26]

Patchset 1 (id:??) landed as
https://crrev.com/08b24b4f9ea7ad41a31347da059a35fb4ad592b3
Cr-Commit-Position: refs/heads/master@{#315322}