[MD Extensions] Implement opening tab-style options pages

chrome/browser/resources/md_extensions/detail_view.html

 <link rel="import" href="chrome://resources/html/cr.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-flex-layout/iron-flex-layout-classes.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icons/iron-icons.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-checkbox/paper-checkbox.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-styles/color.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/neon-animation/neon-animatable-behavior.html">
 <link rel="import" href="chrome://extensions/animation_helper.html">
 <link rel="import" href="chrome://extensions/item_source.html">
 
 <dom-module id="extensions-detail-view">
   <style include="iron-flex"></style>
   <template>
     <style>
+      [hidden] {
+        display: none !important;
+      }
       #main {
         background-color: white;
         height: 800px;
         width: 90%;
       }
       #top-bar {
         align-items: center;
         color: var(--paper-grey-600);
         display: flex;
         height: 40px;
@@ skipping 26 matching lines @@
         --primary-text-color: var(--paper-grey-800);
       }
       ul {
         -webkit-padding-start: 20px;
         margin: 0;
       }
     </style>
     <div id="main">
       <div id="top-bar">
         <paper-icon-button id="close-button" icon="arrow-back"
             on-click="onCloseButtonClick_"></paper-icon-button>

[michaelpg, 2016/09/15 02:13:46]

on-tap

[Devlin, 2016/09/15 16:42:17]

Done.

         <span id="name">[[data.name]]</span>
         <paper-icon-button id="open-in-webstore" icon="open-in-new">
         </paper-icon-button>
-        <paper-icon-button id="options" icon="settings">
+        <paper-icon-button id="options" icon="settings"
+            on-click="onOptionsButtonClick_"

[michaelpg, 2016/09/15 02:13:46]

on-tap

[Devlin, 2016/09/15 16:42:17]

Done.

+            hidden$="[[!shouldShowOptionsButton_(data.*)]]">
         </paper-icon-button>
       </div>
       <div class="section">
         <div class="section-title">$i18n{itemDescriptionLabel}</div>
         <div class="section-content">[[data.description]]</div>
       </div>
       <div class="section">
         <div class="section-title">$i18n{itemVersion}</div>
         <div class="section-content">[[data.version]]</div>
       </div>
@@ skipping 60 matching lines @@
       <div class="section">
         <div class="section-title">$i18n{itemSource}</div>
         <div class="section-content">
           [[computeSourceString_(data.*)]]
         </div>
       </div>
     </div>
   </template>
   <script src="chrome://extensions/detail_view.js"></script>
 </dom-module>