history: add context menu buttons to the tab order.

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 2ac6f40dc6f708cfcd49ec489e5aa4fc00aa7295..39b9065ba85008bbb3c3cbccbef281dcb5337e28 100644
--- a/chrome/browser/resources/history/other_devices.js
+++ b/chrome/browser/resources/history/other_devices.js
@@ -185,6 +185,7 @@ Device.prototype.getDOMNode = function(maxNumTabs, row) {
   heading.addEventListener('contextmenu', handleDropDownFocus);
 
   var dropDownButton = new cr.ui.ContextMenuButton;
+  dropDownButton.tabIndex = 0;

[dmazzoni, 2014/10/10 05:31:18]

Should this be upstreamed to cr.ui.ContextMenuButton? When would you ever not
want it to be focusable?

   dropDownButton.classList.add('drop-down');
   dropDownButton.addEventListener('mousedown', function(event) {
       handleDropDownFocus(event);