Bug 1639399 - expose uniqueID property on the xpcAccessible. r=Jamie

Differential Revision: https://phabricator.services.mozilla.com/D76072

accessible/interfaces/nsIAccessible.idl

@@ -74,6 +74,13 @@ interface nsIAccessible : nsISupports
    */
   readonly attribute long indexInParent;
 
+  /**
+   * The unique identifier of the accessible. ID is only guaranteed to be unique
+   * per document (Windows IDs are unique even across documents, but that is
+   * Windows specific and not exposed to core).
+   */
+  readonly attribute long long uniqueID;
+
   /**
    * The DOM node this nsIAccessible is associated with.
    */

accessible/tests/browser/e10s/browser.ini

@@ -21,6 +21,7 @@ skip-if = (os == "linux" && bits == 64) || (debug && os == "mac") || (debug && o
 [browser_caching_relations.js]
 [browser_caching_states.js]
 [browser_caching_value.js]
+[browser_caching_uniqueid.js]
 
 # Events tests
 [browser_events_announcement.js]

accessible/tests/browser/e10s/browser_caching_uniqueid.js

@@ -0,0 +1,30 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+/**
+ * Test UniqueID property.
+ */
+addAccessibleTask(
+  '<div id="div"></div>',
+  async function(browser, accDoc) {
+    const div = findAccessibleChildByID(accDoc, "div");
+    const accUniqueID = await invokeContentTask(browser, [], () => {
+      const accService = Cc["@mozilla.org/accessibilityService;1"].getService(
+        Ci.nsIAccessibilityService
+      );
+
+      return accService.getAccessibleFor(content.document.getElementById("div"))
+        .uniqueID;
+    });
+
+    is(
+      accUniqueID,
+      div.uniqueID,
+      "Both proxy and the accessible return correct unique ID."
+    );
+  },
+  { iframe: true, remoteIframe: true }
+);

accessible/xpcom/xpcAccessible.cpp

@@ -161,6 +161,21 @@ xpcAccessible::GetIndexInParent(int32_t* aIndexInParent) {
   return *aIndexInParent != -1 ? NS_OK : NS_ERROR_FAILURE;
 }
 
+NS_IMETHODIMP
+xpcAccessible::GetUniqueID(int64_t* aUniqueID) {
+  NS_ENSURE_ARG_POINTER(aUniqueID);
+
+  if (IntlGeneric().IsNull()) return NS_ERROR_FAILURE;
+
+  if (IntlGeneric().IsAccessible()) {
+    *aUniqueID = reinterpret_cast<uintptr_t>(Intl()->UniqueID());
+  } else if (IntlGeneric().IsProxy()) {
+    *aUniqueID = IntlGeneric().AsProxy()->ID();
+  }
+
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 xpcAccessible::GetDOMNode(nsINode** aDOMNode) {
   NS_ENSURE_ARG_POINTER(aDOMNode);

accessible/xpcom/xpcAccessible.h

@@ -34,6 +34,7 @@ class xpcAccessible : public nsIAccessible {
   NS_IMETHOD GetChildren(nsIArray** aChildren) final;
   NS_IMETHOD GetIndexInParent(int32_t* aIndexInParent) final;
 
+  NS_IMETHOD GetUniqueID(int64_t* aUniqueID) final;
   NS_IMETHOD GetDOMNode(nsINode** aDOMNode) final;
   NS_IMETHOD GetId(nsAString& aID) final;
   NS_IMETHOD GetDocument(nsIAccessibleDocument** aDocument) final;