webui: remove FocusManager.disableMouseFocusOnButtons().

ui/webui/resources/js/cr/ui/focus_manager.js

Index: ui/webui/resources/js/cr/ui/focus_manager.js
diff --git a/ui/webui/resources/js/cr/ui/focus_manager.js b/ui/webui/resources/js/cr/ui/focus_manager.js
index 3d2fac9020bac4467bbf4e9814bd34582cad3d63..2142efd2ee75392600a4e7ec4df512c880390c55 100644
--- a/ui/webui/resources/js/cr/ui/focus_manager.js
+++ b/ui/webui/resources/js/cr/ui/focus_manager.js
@@ -194,38 +194,6 @@ cr.define('cr.ui', function() {
     },
   };
 
-  /**
-   * Disable mouse-focus for button controls.
-   * Button form controls are mouse-focusable since Chromium 30.  We want the
-   * old behavior in some WebUI pages.
-   */
-  FocusManager.disableMouseFocusOnButtons = function() {
-    document.addEventListener('mousedown', function(event) {
-      if (event.defaultPrevented)
-        return;
-      var node = event.target;
-      var tagName = node.tagName;
-      if (tagName != 'BUTTON' && tagName != 'INPUT') {
-        do {
-          node = node.parentNode;
-          if (!node || node.nodeType != Node.ELEMENT_NODE)
-            return;
-        } while (node.tagName != 'BUTTON');
-      }
-      var type = node.type;
-      if (type == 'button' || type == 'reset' || type == 'submit' ||
-          type == 'radio' || type == 'checkbox') {
-        if (document.activeElement != node)
-          document.activeElement.blur();
-
-        // Focus the current window so that if the active element is in another
-        // window, it is deactivated.
-        window.focus();
-        event.preventDefault();
-      }
-    }, false);
-  };
-
   return {
     FocusManager: FocusManager,
   };