[MD History] Add routing to the synced devices page.

chrome/browser/resources/md_history/side_bar.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/app-layout/app-drawer/app-drawer.html">
+<link rel="import" href="chrome://resources/polymer/v1_0/iron-flex-layout/iron-flex-layout.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-selector/iron-selector.html">
-<link rel="import" href="chrome://resources/polymer/v1_0/paper-item/paper-item.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-styles/color.html">
+<link rel="import" href="chrome://resources/polymer/v1_0/paper-styles/typography.html">
 <link rel="import" href="chrome://history/browser_service.html">
 <link rel="import" href="chrome://history/shared_style.html">
 
 <dom-module id="history-side-bar">
   <template>
     <style include="shared-style">
       :host {
         display: block;
         padding-top: 5px;
         width: var(--side-bar-width);
@@ skipping 17 matching lines @@
       div.separator {
         background-color: rgba(0, 0, 0, 0.08);
         height: 1px;
         margin: 8px 0;
       }
 
       #clear-browsing-data {
         text-transform: uppercase;
       }
 
-      paper-item {
+      iron-selector {
+        -webkit-user-select: none;
+        background-color: transparent;
+        color: #5a5a5a;
+      }
+
+      iron-selector a {
+        @apply(--paper-font-subhead);
         -webkit-padding-start: 25px;
+        align-items: center;
+        box-sizing: border-box;
+        color: inherit;
         cursor: pointer;
+        display: flex;
         font-size: 14px;
         font-weight: 500;
+        min-height: 48px;
+        outline: none;
+        position: relative;
+        text-decoration: none;
       }
 
-      paper-item.iron-selected {
+      iron-selector a:focus {
+        outline: 0;
+        position: relative;
+      }
+
+      iron-selector a:focus::before {
+        @apply(--layout-fit);
+
+        background: currentColor;
+        content: '';
+        opacity: var(--dark-divider-opacity);
+        pointer-events: none;
+      }
+
+      iron-selector a.iron-selected {
         color: var(--google-blue-500);
         font-weight: 500;
       }
 
       iron-selector {
         -webkit-user-select: none;
         color: #5a5a5a;
       }
     </style>
 
     <app-drawer id="drawer" tabindex="0" on-focus="onDrawerFocus_" swipe-open
         align="start">
       <div id="drawer-header">
         <h1>$i18n{title}</h1>
       </div>
       <iron-selector id="menu" selected="{{selectedPage}}"
-          selectable=".page-item" attr-for-selected="view-id"
+          selectable=".page-item" attr-for-selected="path"
+          fallback-selection="history"
           on-iron-activate="onSelectorActivate_">
-        <paper-item view-id="history" class="page-item">
+        <a href="/" class="page-item" path="history">

[Dan Beam, 2016/07/15 04:23:40]

why is it worthwhile to switch to <a href> here?  do you really want
right/middle click options this badly?  settings did not feel the need to do
this, as I don't really think there's a big use case for right click > copy URL
or opening in new tabs.

[calamity, 2016/07/15 06:22:02]

I'm not 100% sure if this is true, but it seems that app-route is 'nicer' if you
use <a href>s to change your state. It's the way SHOP does it as well.

I did have a data-bound version earlier, but it was getting complicated to
decide who has responsibility for what. <a href>s mean that the data flow is
always top down (click, app-location notifies down the route hierarchy and
everyone changes as necessary).

This is a bit messy with all the CSS, but once paper-item-shared-styles is fixed
to be more... shareable, the nastiness above will hopefully go away.

           $i18n{historyMenuItem}
-        </paper-item>
-        <paper-item view-id="synced-devices" class="page-item">
+        </a>
+        <a href="/syncedTabs" class="page-item" path="syncedTabs">
           $i18n{openTabsMenuItem}
-        </paper-item>
+        </a>
         <div class="separator"></div>
-        <paper-item on-tap="onClearBrowsingDataTap_" id="clear-browsing-data">
+        <a on-tap="onClearBrowsingDataTap_" id="clear-browsing-data">

[tsergeant, 2016/07/15 03:56:14]

An <a> without an href="" is kind of like a plain old span, which means you
can't tab to it and you can't right click or middle click it like a regular
link.

You can improve this by doing <a href="#" ...>, which lets you tab to it and use
enter or space to open CBD. But then if you middle click the link, you get
chrome://history open in a new tab.

The best solution here seems to be:
<a href="chrome://settings/clearBrowserData" on-tap="...">

Then in onClearBrowsingDataTap_, preventDefault on the tap event.

This way:
- the <a> has the correct a11y values
- clicking or pressing enter uses the chrome.send version
- middle clicking or right-click -> new tab works as expected.

[calamity, 2016/07/15 06:22:02]

Ace Investigation. Done.

           $i18n{clearBrowsingData}
-        </paper-item>
+        </a>
       </iron-selector>
     </app-drawer>
   </template>
   <script src="chrome://history/side_bar.js"></script>
 </dom-module>