Allow for focus on role unknown nodes

R=akihiroota@chromium.org

Test: browser_tests --gtest_filter=ChromeVox*.*Unknown
Change-Id: I918f738fc0e9fdee1db2bec579e43a8f3a0984e6
Fixed: 934968
AX-Relnotes: when a permission dialog pops up, ChromeVox places focus correctly.
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2283928
Commit-Queue: David Tseng <dtseng@chromium.org>
Reviewed-by: Akihiro Ota <akihiroota@chromium.org>
Cr-Commit-Position: refs/heads/master@{#785842}

chrome/browser/resources/chromeos/accessibility/chromevox/background/background_test.js

@@ -2659,3 +2659,42 @@ TEST_F('ChromeVoxBackgroundTest', 'HoverSkipsContainers', function() {
             .replay();
       });
 });
+
+TEST_F('ChromeVoxBackgroundTest', 'FocusOnUnknown', function() {
+  const mockFeedback = this.createMockFeedback();
+  this.runWithLoadedTree(
+      `
+    <p>start</p>
+    <div role="group" tabindex=0>
+      <p>hello<p>
+    </div>
+    <div role="group" tabindex=0></div>
+  `,
+      function(root) {
+        const [group1, group2] = root.findAll({role: RoleType.GROUP});
+        assertNotNullNorUndefined(group1);
+        assertNotNullNorUndefined(group2);
+        Object.defineProperty(group1, 'role', {
+          get() {
+            return chrome.automation.RoleType.UNKNOWN;
+          }
+        });
+        Object.defineProperty(group2, 'role', {
+          get() {
+            return chrome.automation.RoleType.UNKNOWN;
+          }
+        });
+
+        const evt2 = new CustomAutomationEvent(EventType.FOCUS, group2, '', []);
+        const currentRange = ChromeVoxState.instance.currentRange;
+        DesktopAutomationHandler.instance.onFocus(evt2);
+        assertEquals(currentRange, ChromeVoxState.instance.currentRange);
+
+        const evt1 = new CustomAutomationEvent(EventType.FOCUS, group1, '', []);
+        mockFeedback
+            .call(DesktopAutomationHandler.instance.onFocus.bind(
+                DesktopAutomationHandler.instance, evt1))
+            .expectSpeech('hello')
+            .replay();
+      });
+});

chrome/browser/resources/chromeos/accessibility/chromevox/background/desktop_automation_handler.js

@@ -17,6 +17,7 @@ goog.require('editing.TextEditHandler');
 
 goog.scope(function() {
 const AutomationNode = chrome.automation.AutomationNode;
+const Dir = constants.Dir;
 const EventType = chrome.automation.EventType;
 const RoleType = chrome.automation.RoleType;
 const StateType = chrome.automation.StateType;
@@ -206,7 +207,7 @@ DesktopAutomationHandler = class extends BaseAutomationHandler {
       this.textEditHandler_ = null;
     }
 
-    const node = evt.target;
+    let node = evt.target;
 
     // Discard focus events on embeddedObject and webView.
     if (node.role == RoleType.EMBEDDED_OBJECT ||
@@ -215,7 +216,15 @@ DesktopAutomationHandler = class extends BaseAutomationHandler {
     }
 
     if (node.role == RoleType.UNKNOWN) {
-      return;
+      // Ideally, we'd get something more meaningful than focus on an unknown
+      // node, but this does sometimes occur. Sync downward to a more reasonable
+      // target.
+      node = AutomationUtil.findNodePre(
+          node, Dir.FORWARD, AutomationPredicate.object);
+
+      if (!node) {
+        return;
+      }
     }
 
     if (!node.root) {