Remove dead code for system VK.

ui/keyboard/resources/elements/kb-key-sequence.js

-// Copyright 2014 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.
-
-(function() {
-
-  var metadata = null;
-
-  function getKeyCodeAndModifiers(keyCodeIndex) {
-    if (!metadata)
-      metadata = document.createElement('kb-key-codes');
-    return metadata.GetKeyCodeAndModifiers(keyCodeIndex);
-  }
-
-  Polymer('kb-key-sequence', {
-    /**
-     * Generates the DOM structure to replace (expand) this kb-key-sequence.
-     */
-    generateDom: function() {
-      var replacement = document.createDocumentFragment();
-      var newKeys = this.getAttribute('keys');
-      var newHintTexts = this.getAttribute('hintTexts');
-      var keyCodes = this.getAttribute('hintCodes') || newKeys;
-      var invert = this.getAttribute('invert');
-      if (newKeys) {
-        if (newHintTexts && newKeys.length != newHintTexts.length) {
-          console.error('keys and hintTexts do not match');
-          return;
-        }
-        if (keyCodes && newKeys.length != keyCodes.length) {
-           console.error('keys and keyCodes do not match');
-          return;
-        }
-
-        for (var i = 0; i < newKeys.length; i++) {
-          var key = document.createElement('kb-key');
-          key.innerText = newKeys[i];
-          key.accents = newKeys[i];
-          if (newHintTexts)
-            key.hintText = newHintTexts[i];
-          var keyCodeIndex = keyCodes[i];
-          if (invert) {
-            key.invert = true;
-            key.char = newKeys[i];
-            keyCodeIndex = key.hintText;
-          }
-          var state = getKeyCodeAndModifiers(keyCodeIndex);
-          if (state) {
-            key.keyCode = state.keyCode;
-            key.keyName = state.keyName;
-            key.shiftModifier = state.shiftModifier;
-          }
-          replacement.appendChild(key);
-        }
-      }
-      return replacement;
-    }
-  });
-})();
-