Convert Media Router WebUI <button>s to <paper-button>s.

chrome/browser/resources/media_router/media_router_common.css

Index: chrome/browser/resources/media_router/media_router_common.css
diff --git a/chrome/browser/resources/media_router/media_router_common.css b/chrome/browser/resources/media_router/media_router_common.css
index 00597408cd50f893084e96a6e9e117c01a809053..7ed08387e0a8e3d1ffe25b5abef55930086bb3a5 100644
--- a/chrome/browser/resources/media_router/media_router_common.css
+++ b/chrome/browser/resources/media_router/media_router_common.css
@@ -2,13 +2,12 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file. */
 
-button {
-  border: 1px solid rgb(193, 193, 195);
+.button {
+  background-color: rgb(238, 238, 238);

[mark a. foltz, 2015/05/13 01:50:32]

Does paper provide a default color for buttons, or do we have to set it
ourselves?  How are we certain that this color will match other paper buttons in
Chrome?

[Jeremy Klein, 2015/05/13 02:28:15]

When you guys upgrade to 0.8, you'll be able to use these:

https://code.google.com/p/chromium/codesearch#chromium/src/third_party/polyme...

[apacible, 2015/05/13 14:31:18]

These are current placeholder colors, based on our old design. We'll update
these to match when we get final UX specs/redlines (and switch to 0.8), which
should match the other paper buttons in Chrome. 

   color: rgb(44, 44, 44);
   cursor: pointer;
   font-size: 1em;
   font-weight: bold;
-  height: 32px;
   overflow: hidden;
   text-align: center;
   width: 100%;