Use core/paper elements in media-router-container.

Use core/paper elements in media-router-container.

- Use core-toolbar for header.
- Change close button div to a paper-icon-button.
- Remove close-gray.png and close-gray2x.png.
- Remove unneeded CSS, modifies some positioning.

Committed: https://crrev.com/6285aa894b72e6eb5e5d584ac0c17ebbd77c9a45
Cr-Commit-Position: refs/heads/master@{#329342}

[apacible, 2015-05-11 22:56:52]

apacible@chromium.org changed reviewers:
+ jhawkins@chromium.org, jlklein@chromium.org, mfoltz@chromium.org,
michaelpg@chromium.org

[apacible, 2015-05-11 23:10:14]

PTAL, thanks!

The other components of the media-router-container are being
core/paper-element-ified in other CLs.

Our new design for the UI will be finalized soon. I'll address UI components
such as the cast mode picker as a drop-down menu and having enough space for
localized strings (see cast mode picker RTL) in future CLs.

Screenshots --

Sink Picker:
LTR: https://screenshot.googleplex.com/jgFtEPjFSB2.png
RTL: https://screenshot.googleplex.com/XrxdxxrowtL.png

Cast Mode Picker:
LTR: https://screenshot.googleplex.com/TayGxm9W7fP.png
RTL: https://screenshot.googleplex.com/KmayGJ1kpQu.png

Unchanged:
Route Details: https://screenshot.googleplex.com/bRVJraTeaCq.png
Issue (non-blocking): https://screenshot.googleplex.com/rG1RDaod7oL.png
Issue (blocking): https://screenshot.googleplex.com/70qXs1M204m.png

[mark a. foltz, 2015-05-11 23:40:49]

lgtm

[apacible, 2015-05-12 02:51:23]

The CQ bit was checked by apacible@chromium.org

[apacible, 2015-05-12 02:51:23]

The patchset sent to the CQ was uploaded after l-g-t-m from mfoltz@chromium.org
Link to the patchset: https://codereview.chromium.org/1134463008/#ps20001
(title: "Rebase")

[commit-bot: I haz the power, 2015-05-12 02:51:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1134463008/20001

[commit-bot: I haz the power, 2015-05-12 03:34:06]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-05-12 03:34:53]

Patchset 2 (id:??) landed as
https://crrev.com/6285aa894b72e6eb5e5d584ac0c17ebbd77c9a45
Cr-Commit-Position: refs/heads/master@{#329342}