Removing sync from file_util::Delete for ChromeOS.
Removing sync from file_util::Delete for ChromeOS.

This was added to address a problem with SD cards not always deleting
files that were deleted from the ChromeOS file browser. Since it
doesn't always fix the problem anyhow, and since the file browser
isn't in beta, I'm removing the extra sync call, because it increases
the time it takes to run recursive delete by about three orders of
magnitude, and was slowing down some tests.

I've filed bug http://code.google.com/p/chromium-os/issues/detail?id=7196
so we can address this at a later time.

[This has already been reviewed and LGTM'd here:
http://codereview.chromium.org/3697005/show]

BUG=none
TEST=ran base unittests

Review URL: http://codereview.chromium.org/3706005

git-svn-id: http://src.chromium.org/svn/trunk/src@62245 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 5651762ed95a7b99d02b7571596ee217d7f17264
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser