Use aria range values for sliders

chrome/browser/resources/chromeos/chromevox/cvox2/background/output.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.
 
 /**
  * @fileoverview Provides output services for ChromeVox.
  */
 
 goog.provide('Output');
 goog.provide('Output.EventType');
@@ skipping 508 matching lines @@
     },
     region: {
       speak: '$nameOrTextContent'
     },
     row: {
       enter: '$node(tableRowHeader)'
     },
     rowHeader: {
       speak: '$descendants $state'
     },
     slider: {

[dmazzoni, 2016/11/17 23:07:41]

You should expose range value attributes for these roles, it's potentially legal
for any of them:

      AX_ROLE_PROGRESS_INDICATOR
      AX_ROLE_METER
      AX_ROLE_SCROLL_BAR
      AX_ROLE_SLIDER
      AX_ROLE_SPIN_BUTTON

Alternatively, could you just trust that Blink won't expose these attributes
unless
they're relevant? I think there are quite a few rare attributes that might be
simpler to handle that way.

[David Tseng, 2017/01/20 22:18:05]

It would be, but it also prevents us from fine-tuning the output for each role
and clearly seeing how the output should look for a given role.

This is especially considering the confusion/disagreement about how these things
should bhave anyway (e.g. for meter:
https://github.com/w3c/aria/issues/451).

 I've added an abstractRange role so each of the above types can inherit from it
so it gives us good behavoir but also with the option to specialize if needed.

-      speak: '$earcon(SLIDER) @describe_slider($value, $name) $description ' +
+      speak:
+          '$if($valueForRange, $valueForRange) ' +

[dmazzoni, 2016/11/17 23:07:41]

I think $value is almost always better because it should contain aria-valuetext
if present, but the value otherwise.

[David Tseng, 2017/01/20 22:18:05]

ok, done.

+          '$if($minValueForRange, @aria_value_min($minValueForRange)) ' +
+          '$if($maxValueForRange, @aria_value_max($maxValueForRange)) ' +
+          '$earcon(SLIDER) @describe_slider($value, $name) $description ' +
           '$state'
     },
     staticText: {
       speak: '$name='
     },
     switch: {
       speak: '$if($checked, $earcon(CHECK_ON), $earcon(CHECK_OFF)) ' +
           '$if($checked, @describe_switch_on($name), ' +
           '@describe_switch_off($name)) $description $state'
     },
@@ skipping 521 matching lines @@
             this.append_(buff, Msgs.getMsg('selected'));
           } else {
             this.append_(buff, text, options);
           }
         } else if (token == 'name') {
           options.annotation.push(token);
           var earcon = node ? this.findEarcon_(node, opt_prevNode) : null;
           if (earcon)
             options.annotation.push(earcon);
           this.append_(buff, node.name, options);
+        } else if (token == 'description') {
+          if (node.name == node.description)
+            return;
+
+          options.annotation.push(token);
+          this.append_(buff, node.description, options);
         } else if (token == 'urlFilename') {
           options.annotation.push('name');
           var url = node.url;
           var filename = '';
           if (url.substring(0, 4) != 'data') {
             filename =
                 url.substring(url.lastIndexOf('/') + 1, url.lastIndexOf('.'));
 
             // Hack to not speak the filename if it's ridiculously long.
             if (filename.length >= 30)
@@ skipping 171 matching lines @@
           var msgId =
               this.formatOptions_.braille ? resolvedInfo.msgId + '_brl' :
               resolvedInfo.msgId;
           var msg = Msgs.getMsg(msgId);
           this.append_(buff, msg, options);
         } else if (tree.firstChild) {
           // Custom functions.
           if (token == 'if') {
             var cond = tree.firstChild;
             var attrib = cond.value.slice(1);
-            if (node[attrib] || node.state[attrib])
+            if (node[attrib] !== undefined || node.state[attrib])
               this.format_(node, cond.nextSibling, buff);
             else
               this.format_(node, cond.nextSibling.nextSibling, buff);
           } else if (token == 'earcon') {
             // Ignore unless we're generating speech output.
             if (!this.formatOptions_.speech)
               return;
 
             options.annotation.push(
                 new Output.EarconAction(tree.firstChild.value));
@@ skipping 555 matching lines @@
   /**
    * Gets the output buffer for braille.
    * @return {!Spannable}
    */
   get brailleOutputForTest() {
     return this.mergeBraille_(this.brailleBuffer_);
   }
 };
 
 });  // goog.scope