Add <a is="action-link">, a web component extension of <a> for in-page actions.

chrome/browser/resources/history/other_devices.js

Index: chrome/browser/resources/history/other_devices.js
diff --git a/chrome/browser/resources/history/other_devices.js b/chrome/browser/resources/history/other_devices.js
index 3043b213bcb6712b7ecad61c3d149dfb83f6cb46..f2e9d6b76d52c7b1891bad2717fe9829f6d4e9f0 100644
--- a/chrome/browser/resources/history/other_devices.js
+++ b/chrome/browser/resources/history/other_devices.js
@@ -293,14 +293,12 @@ Device.prototype.createSessionContents_ = function(maxNumTabs) {
   }
 
   if (numTabsHidden > 0) {
-    var moreLinkButton = createElementWithClassName('button',
-        'device-show-more-tabs link-button');
-    moreLinkButton.addEventListener('click', this.view_.increaseRowHeight.bind(
+    var moreLink = document.createElement('a', 'action-link');
+    moreLink.classList.add('device-show-more-tabs');
+    moreLink.addEventListener('click', this.view_.increaseRowHeight.bind(
         this.view_, this.row_, numTabsHidden));
-    var xMore = loadTimeData.getString('xMore');
-    moreLinkButton.appendChild(
-        document.createTextNode(xMore.replace('$1', numTabsHidden)));
-    contents.appendChild(moreLinkButton);
+    moreLink.textContent = loadTimeData.getStringF('xMore', numTabsHidden);
+    contents.appendChild(moreLink);
   }
 
   return contents;