[Files.app] Make the file-type dropbox at the bottom hidden by default

[Files.app] Make the file-type dropbox at the bottom hidden by default

This is a reland of r233875. The previous patch didn't make the dropbox hidden in the open dialog. This patch adds change it as well as the save-as dialog.

BUG=316133
TEST=manually tested
R=hirono@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=234982

[yoshiki, 2013-11-12 20:41:46]

@hirono, PTAL. Sorry for your double works. Thanks.

[hirono, 2013-11-12 20:53:44]

lgtm! Thanks!

[commit-bot: I haz the power, 2013-11-12 20:57:17]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/yoshiki@chromium.org/63673004/1

[commit-bot: I haz the power, 2013-11-12 21:52:43]

Sorry for I got bad news for ya.
Compile failed with a clobber build on linux_chromeos_clang.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_chro...
Your code is likely broken or HEAD is junk. Please ensure your
code is not broken then alert the build sheriffs.
Look at the try server FAQ for more details.

[yoshiki, 2013-11-14 00:37:23]

Committed patchset #1 manually as r234982 (presubmit successful).

[mtomasz, 2013-11-21 04:24:10]

https://codereview.chromium.org/63673004/diff/1/chrome/browser/resources/file...
File chrome/browser/resources/file_manager/foreground/js/file_manager.js
(right):

https://codereview.chromium.org/63673004/diff/1/chrome/browser/resources/file...
chrome/browser/resources/file_manager/foreground/js/file_manager.js:1315: //
There is in fact no choice, show the selector.
Please fix this comment, it is wrong.