Fix tab switch recovery

ChromeVox's expectations with regard to tab switch recovery have changed. Namely:
- selection events appear to be fired unexpectedly on tabs at various points
- ChromeVox range is no longer over the root web area when a hit test result comes back even when we do want to recover

This change adjusts accordingly to TOT and adds tests for both tab switching and refresh recovery to ensure we don't regress again.

Bug: 887185
Change-Id: I3081830457fb62c14456368a819b00765659a824
Reviewed-on: https://chromium-review.googlesource.com/1246366Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: David Tseng <dtseng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#594815}

chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs

@@ -1738,3 +1738,26 @@ TEST_F('BackgroundTest', 'LinesFilterWhitespace', function() {
         .replay();
   });
 });
+
+TEST_F('BackgroundTest', 'TabSwitchAndRefreshRecovery', function() {
+  var mockFeedback = this.createMockFeedback();
+  this.runWithLoadedTree(function() {/*
+    <p>tab1</p>
+  */}, function(root1) {
+    this.runWithLoadedTree(function() {/*
+      <p>tab2</p>
+    */}, function(root2) {
+      mockFeedback.expectSpeech('tab2')
+          .clearPendingOutput()
+          .call(press(9  /* tab */, {shift: true, ctrl: true}))
+          .expectSpeech('tab1')
+          .clearPendingOutput()
+          .call(press(9  /* tab */, {ctrl: true}))
+          .expectSpeech('tab2')
+          .clearPendingOutput()
+          .call(press(82  /* R */, {ctrl: true}))
+          .expectSpeech('tab2')
+          .replay();
+    });
+  });
+});

chrome/browser/resources/chromeos/chromevox/cvox2/background/desktop_automation_handler.js

@@ -213,20 +213,19 @@ DesktopAutomationHandler.prototype = {
    * @param {!AutomationNode} node The hit result.
    */
   onHitTestResult: function(node) {
-    // It is possible that the user moved since we requested a hit test.
-    // The following events occur:
-    // load complete
-    // a hit test with reply is requested
-    // user moves
-    // we end up here
-    // As a result, check to ensure we're still on a root web area, before
-    // continuing.
+    // It is possible that the user moved since we requested a hit test.  Bail
+    // if the current range is valid and on the same page as the hit result (but
+    // not the root).
     if (ChromeVoxState.instance.currentRange &&
         ChromeVoxState.instance.currentRange.start &&
         ChromeVoxState.instance.currentRange.start.node &&
-        ChromeVoxState.instance.currentRange.start.node.role !=
-            RoleType.ROOT_WEB_AREA)
-      return;
+        ChromeVoxState.instance.currentRange.start.node.root) {
+      var cur = ChromeVoxState.instance.currentRange.start.node;
+      if (cur.role != RoleType.ROOT_WEB_AREA &&
+          AutomationUtil.getTopLevelRoot(node) ==
+              AutomationUtil.getTopLevelRoot(cur))
+        return;
+    }
 
     chrome.automation.getFocus(function(focus) {
       if (!focus && !node)
@@ -400,6 +399,9 @@ DesktopAutomationHandler.prototype = {
     if (node.role == RoleType.EMBEDDED_OBJECT || node.role == RoleType.WEB_VIEW)
       return;
 
+    if (node.role == RoleType.UNKNOWN)
+      return;
+
     if (!node.root)
       return;
 
@@ -600,12 +602,10 @@ DesktopAutomationHandler.prototype = {
 
     chrome.automation.getFocus(function(focus) {
       // Desktop tabs get "selection" when there's a focused webview during tab
-      // switching.
-      if (focus.role == RoleType.WEB_VIEW && evt.target.role == RoleType.TAB) {
-        ChromeVoxState.instance.setCurrentRange(
-            cursors.Range.fromNode(focus.firstChild));
+      // switching. Ignore it.
+      if (evt.target.role == RoleType.TAB &&
+          evt.target.root.role == RoleType.DESKTOP)
         return;
-      }
 
       // Some cases (e.g. in overview mode), require overriding the assumption
       // that focus is an ancestor of a selection target.