Implement Increment and Decrement accessible actions

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.
 
 // TODO(nektar): Migrate entire file to Mojoq.
 // 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 four enums, also add to
@@ skipping 214 matching lines @@
     richly_editable,
     selectable,
     selected,
     // Grows vertically, e.g. menu or combo box.
     vertical,
     visited
   };
 
   // An action to be taken on an accessibility node.
   enum AXAction {
+    // Decrement a slider or range control by one step value.
+    decrement,
+
     // Do the default action for an object, typically this means "click".
     do_default,
 
     // Given a point, find the object it corresponds to and fire a
     // HOVER event on it in response.
     hit_test,
 
+    // Increment a slider or range control by one step value.
+    increment,
+
     // Delete any selected text in the control's text value and
     // insert |AXActionData::value| in its place, like when typing or pasting.
     replace_selected_text,
 
     // Scroll any scrollable containers to make the target object visible
     // on the screen.  Optionally pass a subfocus rect in
     // AXActionData.target_rect.
     scroll_to_make_visible,
 
     // Scroll the given object to a specified point on the screen in
@@ skipping 201 matching lines @@
     // occurrence.
     unique_cell_ids,
 
     // For inline text. This is the pixel position of the end of this
     // character within the bounding rectangle of this object, in the
     // direction given by AX_ATTR_TEXT_DIRECTION. For example, for left-to-right
     // text, the first offset is the right coordinate of the first character
     // within the object's bounds, the second offset is the right coordinate
     // of the second character, and so on.
     character_offsets,
-    
+
     // Used for caching. Do not read directly. Use
     // |AXNode::GetOrComputeLineStartOffsets|
     // For all text fields and content editable roots: A list of the start
     // offsets of each line inside this object.
     cached_line_starts,
 
     // For inline text. These int lists must be the same size; they represent
     // the start and end character offset of each word within this text.
     word_starts,
     word_ends
@@ skipping 120 matching lines @@
     // First node is before the second one.
     before,
 
     // Nodes are the same.
     equal,
 
     // First node is after the second one.
     after
   };
 };