Reland Use tree path based recovery by default

This reverts commit 697307bb.

TBR=dmazzoni,chrishall

Bug: 885244,893396
Change-Id: I54ea0a3a8e71e7da39078245318608cc66c28c93
Reviewed-on: https://chromium-review.googlesource.com/c/1286815
Commit-Queue: David Tseng <dtseng@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600586}

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

@@ -1764,7 +1764,12 @@ TEST_F('BackgroundTest', 'TabSwitchAndRefreshRecovery', function() {
           .expectSpeech('tab2')
           .clearPendingOutput()
           .call(press(82  /* R */, {ctrl: true}))
-          .expectSpeech('tab2')
+
+          // ChromeVox stays on the same node due to tree path recovery.
+          .call(() => {
+            assertEquals('tab2',
+                         ChromeVoxState.instance.currentRange.start.node.name);
+          })
           .replay();
     });
   });
@@ -1797,3 +1802,31 @@ TEST_F('BackgroundTest', 'LayoutTable', function() {
         .replay();
   });
 });
+
+TEST_F('BackgroundTest', 'ReinsertedNodeRecovery', function() {
+  var mockFeedback = this.createMockFeedback();
+  this.runWithLoadedTree(function(root) {/*
+    <div>
+      <button id="start">start</button>
+      <button id="hot">hot</button>
+    </div>
+    <button id="end">end</button>
+    <script>
+      var div =       document.body.firstElementChild;
+      var start =       document.getElementById('start');
+      document.getElementById('hot').addEventListener('focus', (evt) => {
+        var hot = evt.target;
+        hot.remove();
+        div.insertAfter(hot, start);
+      });
+    </script>
+  */}, function(root) {
+    mockFeedback.expectSpeech('start')
+        .clearPendingOutput()
+        .call(doCmd('nextObject'))
+        .call(doCmd('nextObject'))
+        .call(doCmd('nextObject'))
+        .expectSpeech('end', 'Button')
+        .replay();
+  });
+});

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

@@ -103,7 +103,7 @@ cursors.Cursor = function(node, index) {
   /** @type {number} @private */
   this.index_ = index;
   /** @type {RecoveryStrategy} */
-  this.recovery_ = new AncestryRecoveryStrategy(node);
+  this.recovery_ = new TreePathRecoveryStrategy(node);
 };
 
 /**