Fixes wrong inheritance of PrefSelect.

chrome/browser/resources/options/pref_ui.js

Index: chrome/browser/resources/options/pref_ui.js
diff --git a/chrome/browser/resources/options/pref_ui.js b/chrome/browser/resources/options/pref_ui.js
index a4a1127c75defebe4b85a0c60d37b4d15cf065aa..b97abaef34b43098ec2e3217687cc861ee6813aa 100644
--- a/chrome/browser/resources/options/pref_ui.js
+++ b/chrome/browser/resources/options/pref_ui.js
@@ -390,7 +390,21 @@ cr.define('options', function() {
 
   PrefSelect.prototype = {
     // Set up the prototype chain
-    __proto__: PrefInputElement.prototype,
+    __proto__: HTMLSelectElement.prototype,

[Dan Beam, 2015/04/20 15:06:26]

keep in mind that settings is being rewritten actively

i think it's better to do one of two things:
1) make an abstract class that is concretely derived into
Pref{Input,Select}Element
2) make a concrete base class that has-an element (rather than is-an element)

both of these sound mildly messy and slightly error prone (but at least we have
typechecking now)

[arv (Not doing code reviews), 2015/04/24 14:22:45]

With ES6 you can do traits.

function PrefTrait(superClass) {
  return class extends superClass {
    handleChange(e) { ... }
  };
}

class PrefSelect extends PrefTrait(HTMLSelectElement) {
  ...
}

class PrefInputElement extends PrefTrait(HTMLInputElement) {
  ...
}

Of course you can desugar that to ES5 if you want.

[Yuki, 2015/04/27 09:22:38]

Looks cool to me.  I defer this re-design task to the maintainers (code owners).

+
+    /**
+     * Initialization function for the cr.ui framework.
+     */
+    decorate: PrefInputElement.prototype.decorate,
+
+    /**
+     * Handle changes to the input element's state made by the user. If a custom
+     * change handler does not suppress it, a default handler is invoked that
+     * updates the associated pref.
+     * @param {Event} event Change event.
+     * @protected
+     */
+    handleChange: PrefInputElement.prototype.handleChange,
 
     /**
      * Update the associated pref when when the user selects an item.
@@ -449,8 +463,62 @@ cr.define('options', function() {
       if (this.onchange)
         this.onchange(event);
     },
+
+    /**
+     * See |updateDisabledState| above.
+     */
+    setDisabled: PrefInputElement.prototype.setDisabled,
+
+    /**
+     * Custom change handler that is invoked first when the user makes changes

[arv (Not doing code reviews), 2015/04/24 14:22:45]

Are these comments just copied from PrefInputElement? If so remove them and add
something like "see PrefInputElement".

[Dan Beam, 2015/04/24 21:48:29]

or [just] @override

[Yuki, 2015/04/27 09:22:38]

Done.

+     * to the input element's state. If it returns false, a default handler is
+     * invoked next that updates the associated pref. If it returns true, the
+     * default handler is suppressed (i.e., this works like stopPropagation or
+     * cancelBubble).
+     * @param {Event} event Input element change event.
+     */
+    customChangeHandler: PrefInputElement.prototype.customChangeHandler,
+
+    /**
+     * Custom change handler that is invoked first when the preference
+     * associated with the input element changes. If it returns false, a default
+     * handler is invoked next that updates the input element. If it returns
+     * true, the default handler is suppressed.
+     * @param {Event} event Input element change event.
+     */
+    customPrefChangeHandler: PrefInputElement.prototype.customPrefChangeHandler,
   };
 
+  /**
+   * The name of the associated preference.
+   */
+  cr.defineProperty(PrefSelect, 'pref', cr.PropertyKind.ATTR);
+
+  /**
+   * The data type of the associated preference, only relevant for derived
+   * classes that support different data types.
+   */
+  cr.defineProperty(PrefSelect, 'dataType', cr.PropertyKind.ATTR);
+
+  /**
+   * Whether this input element is part of a dialog. If so, changes take effect
+   * in the settings UI immediately but are only actually committed when the
+   * user confirms the dialog. If the user cancels the dialog instead, the
+   * changes are rolled back in the settings UI and never committed.
+   */
+  cr.defineProperty(PrefSelect, 'dialogPref', cr.PropertyKind.BOOL_ATTR);
+
+  /**
+   * Whether the associated preference is controlled by a source other than the
+   * user's setting (can be 'policy', 'extension', 'recommended' or unset).
+   */
+  cr.defineProperty(PrefSelect, 'controlledBy', cr.PropertyKind.ATTR);
+
+  /**
+   * The user metric string.
+   */
+  cr.defineProperty(PrefSelect, 'metric', cr.PropertyKind.ATTR);
+
   /////////////////////////////////////////////////////////////////////////////
   // PrefTextField class: