Fix the double-tap to click gesture in touch accessibility mode.

ui/accessibility/ax_enums.idl

 // 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.
 
 // These should be kept in sync with third_party/WebKit/public/web/WebAXEnums.h
 // until the Chromium and Blink trees are merged.
 [camel_case_enum_to_string=true] namespace ui {
 
   // For new entries to the following three enums, also add to
   // chrome/common/extensions/api/automation.idl.
@@ skipping 456 matching lines @@
   [cpp_enum_prefix_override="ax"] enum AXDescriptionFrom {
     description_from_uninitialized = 0,
     description_from_attribute,
     description_from_contents,
     description_from_placeholder,
     description_from_related_element
   };
 
   // Touch gestures on Chrome OS.
   enum AXGesture {
-    double_tap,
+    click,

[David Tseng, 2016/05/26 22:48:24]

I like the gesture_finger_count naming scheme better as it fits in with the
other enum values (e.g. double_tap_1).

[dmazzoni, 2016/05/26 22:59:24]

The reason I realized that double_tap is a bad name for this is because there
are lots of different ways to achieve a click:

1. Double-tap
2. Single-tap (tap again after touch exploration)
3. Split-tap (tap second finger while exploring)

All of these should result in the same behavior, I don't think ChromeVox needs
to distinguish between them. That's why I thought "click" might be better.

     swipe_left_1,
     swipe_up_1,
     swipe_right_1,
     swipe_down_1,
     swipe_left_2,
     swipe_up_2,
     swipe_right_2,
     swipe_down_2,
     swipe_left_3,
     swipe_up_3,
     swipe_right_3,
     swipe_down_3,
     swipe_left_4,
     swipe_up_4,
     swipe_right_4,
     swipe_down_4
   };
 };