Show reasons why nodes are ignored in accessibility sidebar

Source/devtools/protocol.json

 {
     "version": { "major": "1", "minor": "1" },
     "domains": [{
         "domain": "Inspector",
         "hidden": true,
         "types": [],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables inspector domain notifications."
@@ skipping 5030 matching lines @@
                 "enum": [ "checked", "expanded", "pressed", "selected" ],
                 "description": "States which apply to widgets."
             },
             {
                 "id": "AXRelationshipAttributes",
                 "type": "string",
                 "enum": [ "activedescendant", "flowto", "controls", "describedby", "labelledby", "owns" ],
                 "description": "Relationships between elements other than parent/child/sibling."
             },
             {
+                "id": "AXIgnoredReasons",
+                "type": "string",
+                "enum": [ "ariaHidden", "ariaHiddenRoot", "activeModalDialog", "ancestorDisallowsChild", "ignoredRole", "labelFor", "ignoredTagName", "canvasHeight", "canvasWidth", "alt", "noTextAlternative", "focusable", "inheritsPresentation", "labelContainer", "emptyText", "noFallbackContent" ],
+                "description": "Enum of possible reasons why a node could be ignored for accessibility.o"

[dmazzoni, 2015/04/09 05:46:10]

nit: "o" after period

+            },
+            {
                 "id": "AXNode",
                 "type": "object",
                 "properties": [
                     { "name": "nodeId", "$ref": "AXNodeId", "description": "Unique identifier for this node." },
-                    { "name": "role", "$ref": "AXValue", "description": "This <code>Node</code>'s role, whether explicit or implicit." },
+                    { "name": "ignored", "type": "boolean", "description": "Whether this node is ignored for accessibility" },
+                    { "name": "ignoredReasons", "type": "array", "items": { "$ref": "AXProperty" }, "description": "Collection of reasons why this node is hidden.", "optional": true },
+                    { "name": "role", "$ref": "AXValue", "description": "This <code>Node</code>'s role, whether explicit or implicit.", "optional": true},
                     { "name": "name", "$ref": "AXValue", "description": "The accessible name for this <code>Node</code>.", "optional": true },
                     { "name": "description", "$ref": "AXValue", "description": "The accessible description for this <code>Node</code>.", "optional": true },
                     { "name": "value", "$ref": "AXValue", "description": "The value for this <code>Node</code>.", "optional": true },
                     { "name": "help", "$ref": "AXValue", "description": "Help.", "optional": true },
-                    { "name": "properties", "type": "array", "items": { "$ref": "AXProperty" }, "description": "All other properties" }
+                    { "name": "properties", "type": "array", "items": { "$ref": "AXProperty" }, "description": "All other properties", "optional": true }
                 ],
                 "description": "A node in the accessibility tree."
+            },
+            {
+                "id": "AXIgnoredNode",
+                "type": "object",
+                "properties": [
+                    { "name": "nodeId", "$ref": "AXNodeId", "description": "Unique identifier for this ignored node." },
+                    { "name": "ariaHidden", "type": "boolean", "description": "Whether <code>aria-hidden</code> is set directly on this node.", "optional": true },
+                    { "name": "hiddenRoot", "$ref": "AXRelatedNode", "description": "The ancestor node which has <code>aria-hidden</code> set on it causing this node to be hidden.", "optional": true },
+                    { "name": "activeModalDialog", "$ref": "AXRelatedNode", "description": "The active modal dialog causing this element to be inert.", "optional": true },
+                    { "name": "ancestorDisallowsChild", "$ref": "AXRelatedNode", "description": "The ancestor element which disallows this child for any reason (presentational, barren, tree, popup menu items, static text child of menuitems.", "optional": true },
+                    { "name": "ignoredRole", "$ref": "AXValue", "description": "The role of this node, if it is implicitly ignored.", "optional": true },
+                    { "name": "labelFor", "$ref": "AXRelatedNode", "description": "The control for which this node is acting as a label.", "optional": true },
+                    { "name": "hiddenTagName", "type": "string", "description": "If this is a type of element (e.g. a span) which is always hidden.", "optional": true },

[dmazzoni, 2015/04/09 05:53:16]

This one is misleading, because <span> is not always hidden - for example if it
has an ARIA role it will be included.

Basically, this is a heuristic, we should figure out what to do with it.

[aboxhall, 2015/04/09 20:15:36]

Agreed; similarly for noTextAlternative.

+                    { "name": "canvasHeight", "type": "number", "description": "The height of the canvas, if <= 1.", "optional": true },
+                    { "name": "canvasWidth", "type": "number", "description": "The width of the canvas, if <= 1.", "optional": true },
+                    { "name": "alt", "type": "boolean", "description": "Whether this is an image with empty alt text.", "optional": true },

[dmazzoni, 2015/04/09 05:53:16]

Maybe call this emptyAlt?

[aboxhall, 2015/04/09 20:15:36]

This object is actually going to disappear (I created it, then realised I was
better off using a simpler mechanism similar to the way I serialize properties,
but wanted to temporarily keep it around to refer to what types I had in mind
while I was coding the logic). The current logic returns an (empty) string for
this attribute, so this "documentation" is even less useful in this instance!

+                    { "name": "noTextAlternative", "type": "boolean", "description": "Whether this element lacks a text alternative.", "optional": true },

[dmazzoni, 2015/04/09 05:53:16]

This also seems like a heuristic, because lots of nodes with no text alternative
might still be included in the AX tree

+                    { "name": "focusable", "type": "boolean", "description": "Whether this node is  focusable.", "optional": true }
+                ],
+                "description": "An ignored node in the accessibility tree"
             }
         ],
         "commands": [
             {
                 "name": "getAXNode",
                 "parameters": [
                     { "name": "nodeId", "$ref": "DOM.NodeId", "description": "ID of node to get accessibility node for." }
                 ],
                 "returns": [
                     { "name": "accessibilityNode", "$ref": "AXNode", "description": "The <code>Accessibility.AXNode</code> for this DOM node, if it exists.", "optional": true }
                 ],
                 "description": "Fetches the accessibility node for this DOM node, if it exists.",
                 "hidden": true
             }
         ]
     }]
 }