Update bower.json for Polymer elements and add PRESUBMIT.py

third_party/polymer/v1_0/components/paper-slider/paper-slider.css

Index: third_party/polymer/v1_0/components/paper-slider/paper-slider.css
diff --git a/third_party/polymer/v1_0/components/paper-slider/paper-slider.css b/third_party/polymer/v1_0/components/paper-slider/paper-slider.css
index 0fd8682f86b89a7c2af55dc9015cbb2269044d17..af769f4aeeb96d7e1d37d38cb03ee50398dfa6a4 100644
--- a/third_party/polymer/v1_0/components/paper-slider/paper-slider.css
+++ b/third_party/polymer/v1_0/components/paper-slider/paper-slider.css
@@ -1,11 +1,11 @@
 /**
 @license
 Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
-This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE
-The complete set of authors may be found at http://polymer.github.io/AUTHORS
-The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS
+This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
+The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
+The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
 Code distributed by Google as part of the polymer project is also
-subject to an additional IP rights grant found at http://polymer.github.io/PATENTS
+subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */
 
 :host {
@@ -83,6 +83,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
   width: 100%;
   padding: 8px 0;
   margin: -8px 0;
+  background-color: var(--paper-slider-bar-color, transparent);
 }
 
 .ring #sliderBar {