Remove third_party/polymer from .gitignore

Remove third_party/polymer from .gitignore

We should not be ignoring code checked into src.git

Add third_party/polymer/v1_0/components to .gitignore. This is the
local directory that bower is run in (a local sandbox of sorts).
Clear out the checked in contents.

Polymer components that power web UI pages live in
third_party/polymer/v1_0/components-chromium, which is the only
directory we really need to keep.

See also: third_party/polymer/v1_0/reproduce.sh

Also fix the presubmit.

R=dzhioev@chromium.org
BUG=425626
Committed: https://crrev.com/83ff93c5d7c39d73a9261751b397f866fabe7f21
Cr-Commit-Position: refs/heads/master@{#341217}

[Dan Beam, 2015-07-30 22:40:06]

dbeam@chromium.org changed reviewers:
+ jlklein@google.com
- brettw@chromium.org

[Dan Beam, 2015-07-30 22:40:20]

dbeam@chromium.org changed reviewers:
+ jlklein@chromium.org
- jlklein@google.com

[Dan Beam, 2015-07-30 22:42:52]

dbeam@chromium.org changed reviewers:
+ dzhioev@chromium.org
- jlklein@chromium.org

[dzhioev (left Google), 2015-07-30 22:57:02]

On 2015/07/30 22:47:49, Dan Beam wrote:

LGTM

[Dan Beam, 2015-07-30 22:57:35]

The CQ bit was checked by dbeam@chromium.org

[commit-bot: I haz the power, 2015-07-30 22:58:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1269803005/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1269803005/1

[brettw, 2015-07-30 23:08:18]

brettw@chromium.org changed reviewers:
+ brettw@chromium.org

[brettw, 2015-07-30 23:08:19]

lgtm

[commit-bot: I haz the power, 2015-07-30 23:09:24]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-30 23:10:12]

Patchset 1 (id:??) landed as
https://crrev.com/83ff93c5d7c39d73a9261751b397f866fabe7f21
Cr-Commit-Position: refs/heads/master@{#341217}