Implement AutomationNode.querySelector().

extensions/renderer/api/automation/automation_api_helper.cc

+// 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.
+
+#include "extensions/renderer/api/automation/automation_api_helper.h"
+
+#include "content/public/renderer/render_view.h"
+#include "extensions/common/extension_messages.h"
+#include "third_party/WebKit/public/web/WebAXObject.h"
+#include "third_party/WebKit/public/web/WebDocument.h"
+#include "third_party/WebKit/public/web/WebElement.h"
+#include "third_party/WebKit/public/web/WebExceptionCode.h"
+#include "third_party/WebKit/public/web/WebFrame.h"
+#include "third_party/WebKit/public/web/WebNode.h"
+#include "third_party/WebKit/public/web/WebView.h"
+
+namespace extensions {
+
+AutomationApiHelper::AutomationApiHelper(content::RenderView* render_view)
+    : content::RenderViewObserver(render_view) {
+}
+
+AutomationApiHelper::~AutomationApiHelper() {
+}
+
+bool AutomationApiHelper::OnMessageReceived(const IPC::Message& message) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(AutomationApiHelper, message)
+    IPC_MESSAGE_HANDLER(ExtensionMsg_AutomationQuerySelector, OnQuerySelector)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+void AutomationApiHelper::OnQuerySelector(int request_id,
+                                          int acc_obj_id,
+                                          const base::string16& selector) {
+  if (!render_view() || !render_view()->GetWebView() ||
+      !render_view()->GetWebView()->mainFrame()) {
+    Send(new ExtensionHostMsg_AutomationQuerySelector_Result(
+        routing_id(), request_id, "No main frame", 0));
+    return;
+  }
+  blink::WebDocument document =
+      render_view()->GetWebView()->mainFrame()->document();
+  if (document.isNull()) {
+    Send(new ExtensionHostMsg_AutomationQuerySelector_Result(
+        routing_id(), request_id, "No document", 0));
+    return;
+  }
+  blink::WebNode node = document;
+  if (acc_obj_id > 0) {
+    blink::WebAXObject obj = document.accessibilityObjectFromID(acc_obj_id);
+    node = obj.node();
+    while (node.isNull()) {

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

I'm worried this could give you an endless loop if
document.accessibilityObjectFromID returns you a null object above. You should
also terminate the loop if obj.isNull()

Maybe you should write a test that gets an automation node for an element, then
has the page remove that element from the page, then tries to do a query on that
node.

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

Good point. I think it's actually an error if that happens (i.e. we're never
going to find a good DOM node here) so I just returned an error here.
Great idea! Done.

+      obj = obj.parentObject();
+      node = obj.node();
+    }
+  }
+  blink::WebString web_selector(selector);
+  blink::WebExceptionCode ec = 0;
+  blink::WebElement result = node.querySelector(web_selector, ec);
+  int result_acc_obj_id = 0;
+  if (!ec && !result.isNull()) {
+    blink::WebAXObject ax_obj = result.accessibilityObject();
+    if (!ax_obj.isDetached()) {
+      while (ax_obj.accessibilityIsIgnored())
+        ax_obj = ax_obj.parentObject();

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

nit: you can just call ax_obj.parentObjectUnignored() and make it an if instead
of a while loop.

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

It's not in the public api ;_;

+
+      result_acc_obj_id = ax_obj.axID();
+    }
+  }
+  Send(new ExtensionHostMsg_AutomationQuerySelector_Result(
+      routing_id(), request_id, "", result_acc_obj_id));
+}
+
+}  // namespace extensions