[ios] Removed __gCrWeb.common.isFocusable JS API as unused.

ios/web/web_state/js/resources/common.js

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file provides common methods that can be shared by other JavaScripts.
 
 goog.provide('__crWeb.common');
 
 goog.require('__crWeb.base');
 
@@ skipping 61 matching lines @@
    * @return {boolean} true if the |element| is a form control element.
    */
   __gCrWeb.common.isFormControlElement = function(element) {
     var tagName = element.tagName;
     return (tagName === 'INPUT' ||
             tagName === 'SELECT' ||
             tagName === 'TEXTAREA');
   };
 
   /**
-   * Detects focusable elements.
-   * @param {Element} element A DOM element.
-   * @return {boolean} true if the |element| is focusable.
-   */
-  __gCrWeb.common.isFocusable = function(element) {
-    // When the disabled or hidden attributes are present, controls do not
-    // receive focus.
-    if (element.hasAttribute('disabled') || element.hasAttribute('hidden'))
-      return false;
-    return __gCrWeb.common.isFormControlElement(element);
-  };
-
-  /**
    * Returns an array of control elements in a form.
    *
    * This method is based on the logic in method
    *     void WebFormElement::getFormControlElements(
    *         WebVector<WebFormControlElement>&) const
    * in chromium/src/third_party/WebKit/Source/WebKit/chromium/src/
    * WebFormElement.cpp.
    *
    * @param {Element} form A form element for which the control elements are
    *   returned.
@@ skipping 582 matching lines @@
     var plugins = findPluginNodesWithoutFallback_();
     if (plugins.length > 0) {
       // Store the list of plugins in a known place for the replacement script
       // to use, then trigger it.
       __gCrWeb['placeholderTargetPlugins'] = plugins;
       return true;
     }
     return false;
   };
 }());  // End of anonymous object