Added unit tests for auto_scan_manager. Created switch access test target.

chrome/browser/resources/chromeos/switch_access/tree_walker_unittest.gtestjs

 // Copyright 2017 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.
 
 /**
  * Test fixture for tree_walker.js.
  * @constructor
  * @extends {testing.Test}
  */
 function AutomationTreeWalkerUnitTest () {
   testing.Test.call(this);
 };
 
 AutomationTreeWalkerUnitTest.prototype = {
   __proto__: testing.Test.prototype,
 
   /** @override */
   extraLibraries: [
     'tree_walker.js',
   ],
 
+  /** @override */
+  browsePreload: DUMMY_URL,
+
   getSampleTree: function() {
     // root
     //   middle1
     //     leaf1
     //     leaf2
     //     leaf3
     //   middle2
     //     leaf4
     //     leaf5
     let root = {};
@@ skipping 36 matching lines @@
       middle2: middle2,
       leaf1: leaf1,
       leaf2: leaf2,
       leaf3: leaf3,
       leaf4: leaf4,
       leaf5: leaf5
     };
   }
 };
 
+TEST_F('AutomationTreeWalkerUnitTest', 'MoveToNode', function() {
+  let t = this.getSampleTree();
+  let treeWalker = new AutomationTreeWalker();
+
+  let interesting = {focusable: true};
+  t.leaf1.state = interesting;
+  t.leaf2.state = interesting;
+  t.middle2.state = interesting;
+  t.leaf5.state = interesting;
+
+  // Move to next node.
+  assertEquals(t.leaf1, treeWalker.moveToNode(t.root, t.root, true));
+  assertEquals(t.leaf1, treeWalker.moveToNode(t.middle1, t.root, true));
+  assertEquals(t.leaf2, treeWalker.moveToNode(t.leaf1, t.root, true));
+  assertEquals(t.middle2, treeWalker.moveToNode(t.leaf2, t.root, true));
+  assertEquals(t.middle2, treeWalker.moveToNode(t.leaf3, t.root, true));
+  assertEquals(t.leaf5, treeWalker.moveToNode(t.middle2, t.root, true));
+  assertEquals(t.leaf5, treeWalker.moveToNode(t.leaf4, t.root, true));
+  assertEquals(t.leaf1, treeWalker.moveToNode(t.leaf5, t.root, true));
+
+  // Move to previous node.
+  assertEquals(t.middle2, treeWalker.moveToNode(t.leaf5, t.root, false));
+  assertEquals(t.middle2, treeWalker.moveToNode(t.leaf4, t.root, false));
+  assertEquals(t.leaf2, treeWalker.moveToNode(t.middle2, t.root, false));
+  assertEquals(t.leaf2, treeWalker.moveToNode(t.leaf3, t.root, false));
+  assertEquals(t.leaf1, treeWalker.moveToNode(t.leaf2, t.root, false));
+  assertEquals(t.leaf5, treeWalker.moveToNode(t.leaf1, t.root, false));
+  assertEquals(t.leaf5, treeWalker.moveToNode(t.middle1, t.root, false));
+  assertEquals(t.leaf5, treeWalker.moveToNode(t.root, t.root, false));
+});
+
 TEST_F('AutomationTreeWalkerUnitTest', 'GetNextNode', function() {
-  let tree = this.getSampleTree();
+  let t = this.getSampleTree();
   let treeWalker = new AutomationTreeWalker();
 
   let order =
-      [tree.root, tree.middle1, tree.leaf1, tree.leaf2, tree.leaf3,
-      tree.middle2, tree.leaf4, tree.leaf5];
-  let node = tree.root;
+      [t.root, t.middle1, t.leaf1, t.leaf2, t.leaf3,
+      t.middle2, t.leaf4, t.leaf5];
+  let node = t.root;
   for (let i = 0; i < order.length; i++) {
     assertEquals(order[i], node);
     node = treeWalker.getNextNode_(node);
   }
   assertEquals(undefined, node);
 });
 
 TEST_F('AutomationTreeWalkerUnitTest', 'GetPreviousNode', function() {
-  let tree = this.getSampleTree();
+  let t = this.getSampleTree();
   let treeWalker = new AutomationTreeWalker();
 
   let order =
-      [tree.leaf5, tree.leaf4, tree.middle2, tree.leaf3, tree.leaf2,
-      tree.leaf1, tree.middle1, tree.root];
-  let node = tree.leaf5;
+      [t.leaf5, t.leaf4, t.middle2, t.leaf3, t.leaf2,
+      t.leaf1, t.middle1, t.root];
+  let node = t.leaf5;
   for (let i = 0; i < order.length; i++) {
     assertEquals(order[i], node);
     node = treeWalker.getPreviousNode_(node);
   }
   assertEquals(undefined, node);
 });
 
 TEST_F('AutomationTreeWalkerUnitTest', 'GetYoungestDescendant', function() {
-  let tree = this.getSampleTree();
+  let t = this.getSampleTree();
   let treeWalker = new AutomationTreeWalker();
 
-  assertEquals(tree.leaf5, treeWalker.getYoungestDescendant_(tree.root));
-  assertEquals(tree.leaf3, treeWalker.getYoungestDescendant_(tree.middle1));
-  assertEquals(tree.leaf5, treeWalker.getYoungestDescendant_(tree.middle2));
-  assertEquals(undefined, treeWalker.getYoungestDescendant_(tree.leaf1));
-  assertEquals(undefined, treeWalker.getYoungestDescendant_(tree.leaf2));
-  assertEquals(undefined, treeWalker.getYoungestDescendant_(tree.leaf3));
-  assertEquals(undefined, treeWalker.getYoungestDescendant_(tree.leaf4));
-  assertEquals(undefined, treeWalker.getYoungestDescendant_(tree.leaf5));
+  assertEquals(t.leaf5, treeWalker.getYoungestDescendant_(t.root));
+  assertEquals(t.leaf3, treeWalker.getYoungestDescendant_(t.middle1));
+  assertEquals(t.leaf5, treeWalker.getYoungestDescendant_(t.middle2));
+  assertEquals(undefined, treeWalker.getYoungestDescendant_(t.leaf1));
+  assertEquals(undefined, treeWalker.getYoungestDescendant_(t.leaf2));
+  assertEquals(undefined, treeWalker.getYoungestDescendant_(t.leaf3));
+  assertEquals(undefined, treeWalker.getYoungestDescendant_(t.leaf4));
+  assertEquals(undefined, treeWalker.getYoungestDescendant_(t.leaf5));
 });
 
 TEST_F('AutomationTreeWalkerUnitTest', 'IsInteresting', function() {
   let node1 = {};
   let node2 = {state: {}};
   let node3 = {state: {focusable: false}};
   let node4 = {state: {focusable: true}};
   let treeWalker = new AutomationTreeWalker();
 
   assertTrue(treeWalker.isInteresting_(node1) === undefined);
   assertTrue(treeWalker.isInteresting_(node2) === undefined);
   assertFalse(treeWalker.isInteresting_(node3));
   assertTrue(treeWalker.isInteresting_(node4));
 });