Revert 127030 - chromeos: Do not peek at /home/chronos/user/Downloads
Revert 127030 - chromeos: Do not peek at /home/chronos/user/Downloads

Broke ExtensionFileBrowserPrivateApiTest.FileBrowserMount.

Use $HOME/Downloads if running on Linux desktop.

Note that gspencer@ tried to solve this problem in a cleaner way:

  http://codereview.chromium.org/9455073/

However his patch didn't work. I patched it locally, but mount
points like /media/removable didn't show up in the file manager,
and the renderer crashed when I clicked on the "Open downloads folder"
in chrome://downloads, as he warned me beforehand. Hence I decided to
go with a simpler approach in this patch.

BUG=chromium-os:27859
TEST=confirm that contents in ~/Downloads are shown in the file browser on Linux desktop

Review URL: https://chromiumcodereview.appspot.com/9700077

TBR=satorux@chromium.org
Review URL: https://chromiumcodereview.appspot.com/9693067

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@127095 0039d316-1c4b-4281-b951-d872f2087c98

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