Implement AutomationNode.querySelector().

chrome/common/extensions/api/automation.idl

Index: chrome/common/extensions/api/automation.idl
diff --git a/chrome/common/extensions/api/automation.idl b/chrome/common/extensions/api/automation.idl
index 2c48253a86f695ee4cf2d8bf473f5cb6924041dc..6dfe424c3c1862e069a1435058262f20bc664c2a 100644
--- a/chrome/common/extensions/api/automation.idl
+++ b/chrome/common/extensions/api/automation.idl
@@ -220,6 +220,14 @@
     long height;
   };
 
+  // The parameters for a <code>query</code>.
+  dictionary QueryInfo {
+    DOMString? querySelector;
+  };
+
+  // Called when the result for a <code>query</code> is available.
+  callback QueryCallback = void(AutomationNode node);
+
   // An event in the Automation tree.
   [nocompile, noinline_doc] dictionary AutomationEvent {
     // The $(ref:automation.AutomationNode) to which the event was targeted.
@@ -292,6 +300,20 @@
     // Removes a listener for the given event type and event phase.
     static void removeEventListener(
         EventType eventType, AutomationListener listener, boolean capture);
+
+    // Gets the first node in this node's subtree which matches the given CSS
+    // selector and is within the same DOM context.
+    //
+    // If this node doesn't correspond directly with an HTML node in the DOM,
+    // querySelector will be run on this node's nearest HTML node ancestor. Note
+    // that this may result in the query returning a node which is not an
+    // ancestor of this node.

[dmazzoni, 2014/10/30 23:32:42]

nit: ancestor -> descendant

[aboxhall, 2014/10/31 20:32:22]

Oops, done.

+    //
+    // If the selector matches a node which doesn't directly correspond to an
+    // automation node (for example an element within an ARIA widget, where the

[dmazzoni, 2014/10/30 23:32:42]

Your example doesn't make sense, we don't remove nodes from aria widgets from
the automation tree. The simplest example would be nodes that are hidden or not
displayed - they'll be returned by querySelector but won't have an automation
node.

[aboxhall, 2014/10/31 20:32:22]

The are ignoredForAccessibility and don't end up in the tree, as per my test,
but I added comments about hidden elements as well. I can remove the ARIA widget
example if I've missed something...

+    // ARIA widget forms one node of the automation tree), this will return the
+    // nearest ancestor which does correspond to an automation node.
+    static void querySelector(DOMString selector, QueryCallback callback);
   };
 
   // Called when the <code>AutomationRootNode</code> for the page is available.