Implement automatic load of composed/embedded automation trees

chrome/renderer/resources/extensions/automation/automation_node.js

Index: chrome/renderer/resources/extensions/automation/automation_node.js
diff --git a/chrome/renderer/resources/extensions/automation/automation_node.js b/chrome/renderer/resources/extensions/automation/automation_node.js
index fb851690585913880b3ba70de3c1a2f1ea4dbd09..fd2ddd84f14d8361fecf4916d685e5287e9373be 100644
--- a/chrome/renderer/resources/extensions/automation/automation_node.js
+++ b/chrome/renderer/resources/extensions/automation/automation_node.js
@@ -14,6 +14,12 @@ var schema = requireNative('automationInternal').GetSchemaAdditions();
 var utils = require('utils');
 
 /**
+ * Maps an accessibility tree id to an AutomationNode with role type webView.
+ * @type {!Object.<string, string>}
+ */
+var idToWebView_ = {};
+
+/**
  * A single node in the Automation tree.
  * @param {AutomationRootNodeImpl} root The root of the tree.
  * @constructor
@@ -40,18 +46,21 @@ AutomationNodeImpl.prototype = {
   },
 
   parent: function() {
+    if (this.role == schema.RoleType.rootWebArea) {
+      if (idToWebView_[this.treeID])
+        return idToWebView_[this.treeID];
+    }
     return this.rootImpl.get(this.parentID);
   },
 
   firstChild: function() {
-    var node = this.rootImpl.get(this.childIds[0]);
-    return node;
+    return this.lookupWebViewChild_() || this.rootImpl.get(this.childIds[0]);
   },
 
   lastChild: function() {
     var childIds = this.childIds;
-    var node = this.rootImpl.get(childIds[childIds.length - 1]);
-    return node;
+    return this.lookupWebViewChild_() ||
+        this.rootImpl.get(childIds[childIds.length - 1]);
   },
 
   children: function() {
@@ -118,7 +127,6 @@ AutomationNodeImpl.prototype = {
     var parent = this.parent();
     while (parent) {
       path.push(parent);
-      // TODO(aboxhall/dtseng): handle unloaded parent node
       parent = parent.parent();
     }
     var event = new AutomationEvent(eventType, this.wrapper);
@@ -144,6 +152,13 @@ AutomationNodeImpl.prototype = {
         ' attributes=' + $JSON.stringify(this.attributes);
   },
 
+  lookupWebViewChild_: function() {
+    if (this.role != schema.RoleType.webView)
+      return null;
+
+    return automationUtil.idToAutomationRootNode[this.childTreeID];
+  },
+
   dispatchEventAtCapturing_: function(event, path) {
     privates(event).impl.eventPhase = Event.CAPTURING_PHASE;
     for (var i = path.length - 1; i >= 0; i--) {
@@ -194,8 +209,7 @@ AutomationNodeImpl.prototype = {
 
   performAction_: function(actionType, opt_args) {
     // Not yet initialized.
-    if (this.rootImpl.processID === undefined ||
-        this.rootImpl.routingID === undefined ||
+    if (this.rootImpl.treeID === undefined ||
         this.id === undefined) {
       return;
     }
@@ -206,8 +220,7 @@ AutomationNodeImpl.prototype = {
           ' {"interact": true} in the "automation" manifest key.');
     }
 
-    automationInternal.performAction({ processID: this.rootImpl.processID,
-                                       routingID: this.rootImpl.routingID,
+    automationInternal.performAction({ treeID: this.rootImpl.treeID,
                                        automationNodeID: this.id,
                                        actionType: actionType },
                                      opt_args || {});
@@ -255,6 +268,7 @@ var ATTRIBUTE_NAME_TO_ATTRIBUTE_ID = {
  * @const
  */
 var ATTRIBUTE_BLACKLIST = {'activedescendantId': true,
+                           'childTreeId': true,
                            'controlsIds': true,
                            'describedbyIds': true,
                            'flowtoIds': true,
@@ -276,14 +290,13 @@ var ATTRIBUTE_BLACKLIST = {'activedescendantId': true,
  * AutomationNode object.
  * Thus, tree traversals amount to a lookup in our hash.
  *
- * The tree itself is identified by the process id and routing id of the
+ * The tree itself is identified by the accessibility tree id of the
  * renderer widget host.
  * @constructor
  */
-function AutomationRootNodeImpl(processID, routingID) {
+function AutomationRootNodeImpl(treeID) {
   AutomationNodeImpl.call(this, this);
-  this.processID = processID;
-  this.routingID = routingID;
+  this.treeID = treeID;
   this.axNodeDataCache_ = {};
 }
 
@@ -292,6 +305,8 @@ AutomationRootNodeImpl.prototype = {
 
   isRootNode: true,
 
+  role: 'rootWebArea',

[aboxhall, 2014/11/03 17:15:49]

Why is this necessary? Won't this come down in the initial data?

[David Tseng, 2014/11/03 19:31:53]

It was (if we give callers the placeholder node) which comes before any data; no
longer true so removed.

+
   get: function(id) {
     if (id == undefined)
       return undefined;
@@ -353,6 +368,7 @@ AutomationRootNodeImpl.prototype = {
   destroy: function() {
     this.dispatchEvent(schema.EventType.destroyed);
     this.invalidate_(this.wrapper);
+    idToWebView_[this.treeID] = undefined;

[aboxhall, 2014/11/03 17:15:49]

delete idToWebView_[this.treeID] does the same thing and (to me) looks clearer.

[David Tseng, 2014/11/03 19:31:52]

Obsolete.

   },
 
   onAccessibilityEvent: function(eventParams) {
@@ -406,19 +422,10 @@ AutomationRootNodeImpl.prototype = {
       nodeImpl[key] = AutomationAttributeDefaults[key];
     }
     nodeImpl.childIds = [];
-    nodeImpl.loaded = false;
     nodeImpl.id = id;
     delete this.axNodeDataCache_[id];
   },
 
-  load: function(callback) {
-    // TODO(dtseng/aboxhall): Implement.
-    if (!this.loaded)
-      throw 'Unsupported state: root node is not loaded.';
-
-    setTimeout(callback, 0);
-  },
-
   deleteOldChildren_: function(node, newChildIds) {
     // Create a set of child ids in |src| for fast lookup, and return false
     // if a duplicate is found;
@@ -457,6 +464,7 @@ AutomationRootNodeImpl.prototype = {
   createNewChildren_: function(node, newChildIds, updateState) {
     logging.CHECK(node);
     var success = true;
+
     for (var i = 0; i < newChildIds.length; i++) {
       var childId = newChildIds[i];
       var childNode = this.axNodeDataCache_[childId];
@@ -495,6 +503,21 @@ AutomationRootNodeImpl.prototype = {
 
   setData_: function(node, nodeData) {
     var nodeImpl = privates(node).impl;
+
+    if (nodeData.role == schema.RoleType.webView) {

[aboxhall, 2014/11/03 17:15:49]

I think we should have a set of roles which can be host nodes, and check against
that here, or at least a TODO to add it. This logic will be the same for
iframes, right? Anything else?

[David Tseng, 2014/11/03 19:31:53]

Added TODO since that seems a bit early at this point.

+      if (nodeImpl.pendingChildFrame === undefined)
+        nodeImpl.pendingChildFrame = true;

[aboxhall, 2014/11/03 17:15:49]

Do we want to expose the pendingChildFrame property?

[David Tseng, 2014/11/03 19:31:52]

I'd prefer for the caller to check if there are children.

+
+      if (nodeImpl.pendingChildFrame) {
+        nodeImpl.childTreeID = nodeData.intAttributes.childTreeId;
+        idToWebView_[nodeImpl.childTreeID] = node;

[aboxhall, 2014/11/03 17:15:49]

So the id in idToWebView is the ID of the frame it's hosting? Perhaps it would
be better named as frameIdToHostNode or similar?

[David Tseng, 2014/11/03 19:31:52]

Obsolete with other change.

+        automationInternal.enableFrame(nodeImpl.childTreeID);
+        automationUtil.storeTreeCallback(nodeImpl.childTreeID, function(root) {

[aboxhall, 2014/11/03 17:15:49]

What's preventing us from setting root.id as the sole child of nodeImpl here,
and nodeImpl.id as root's parent ID? Node IDs are globally unique, aren't they?
It's entirely possible I'm (again) missing some reason why this wouldn't work,
but it seems like that would be much simpler, and remove the need to keep
idToWebView and lookUpWebChild_(), and thus the need to expose
idToAutomationRootNode to this file.

Please help me figure out what I'm missing here :)

[David Tseng, 2014/11/03 19:31:52]

I'm pretty sure node ids are not globally unique across two different ax trees.
AX tree idds are globally unique.

I suppose we could keep a parentHostID and childRootID on nodeImpl and root
respectively, but I'm not clear how to update those nodes when a destroyed event
comes through.

The idToWebView_ establishes the parent to child mapping while the
idToAutomationRootNode maps the child to parent mapping where child is the
subroot and parent is the host.
No worries; I just spent some time trying to do this; it does indeed make the
code cleaner.

The only reason to not do this and make things slightly more complex is nthat
now JSON.stringify() won't work on some nodes (since they have circular
references).

Other than that, it does clean up things a bit. Thanks.

[aboxhall, 2014/11/03 19:40:18]

Ah of course, they won't be unique if they're in different renderers, which is
the whole point of this.
Oh, this looks great! Thanks for that.

+          nodeImpl.pendingChildFrame = false;
+          nodeImpl.dispatchEvent(schema.EventType.childrenChanged);
+        });
+      }
+    }
     for (var key in AutomationAttributeDefaults) {
       if (key in nodeData)
         nodeImpl[key] = nodeData[key];
@@ -609,9 +632,7 @@ var AutomationNode = utils.expose('AutomationNode',
 
 var AutomationRootNode = utils.expose('AutomationRootNode',

[aboxhall, 2014/11/03 17:15:49]

Do we still need to expose this type at all?

[David Tseng, 2014/11/03 19:31:52]

Still seems useful at least for testing.

                                       AutomationRootNodeImpl,
-                                      { superclass: AutomationNode,
-                                        functions: ['load'],
-                                        readonly: ['loaded'] });
+                                      { superclass: AutomationNode });
 
 exports.AutomationNode = AutomationNode;
 exports.AutomationRootNode = AutomationRootNode;