[Switch Access] Refactor in preparation for improved event handling

Move logic for checking visibility into its own function, centralize
logic to set the current group, and generally improve code cleanliness.

Bug: 1023035
Change-Id: Ib77a31cb11e221a1e0a3f15cc9da35b777d397ce
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1995780Reviewed-by: Akihiro Ota <akihiroota@chromium.org>
Commit-Queue: Anastasia Helfinstein <anastasi@google.com>
Cr-Commit-Position: refs/heads/master@{#732616}

chrome/browser/resources/chromeos/accessibility/switch_access/navigation_manager.js

@@ -48,10 +48,8 @@ class NavigationManager {
     const newGroup = this.node_.asRootNode();
     if (newGroup) {
       this.groupStack_.push(this.group_);
-      this.group_ = newGroup;
+      this.setGroup_(newGroup);
     }
-
-    this.setNode_(this.group_.firstChild);
   }
 
   /**
@@ -230,18 +228,19 @@ class NavigationManager {
     }
 
     this.groupStack_ = [];
-    this.group_ = RootNodeWrapper.buildDesktopTree(this.desktop_);
+    let group = RootNodeWrapper.buildDesktopTree(this.desktop_);
     while (ancestorList.length > 0) {
       let ancestor = ancestorList.pop();
       if (ancestor.role === chrome.automation.RoleType.DESKTOP) {
         continue;
       }
 
-      if (SwitchAccessPredicate.isGroup(ancestor, this.group_)) {
-        this.groupStack_.push(this.group_);
-        this.group_ = RootNodeWrapper.buildTree(ancestor);
+      if (SwitchAccessPredicate.isGroup(ancestor, group)) {
+        this.groupStack_.push(group);
+        group = RootNodeWrapper.buildTree(ancestor);
       }
     }
+    this.setGroup_(group, false /* shouldSetNode */);
   }
 
   /**
@@ -255,17 +254,21 @@ class NavigationManager {
 
     this.group_.onExit();
 
+    let group = this.groupStack_.pop();
     // Find a group that is still valid.
-    do {
-      this.group_ = this.groupStack_.pop();
-    } while (!this.group_.isValid() && this.groupStack_.length);
+    while (!group.isValidGroup() && this.groupStack_.length) {
+      group = this.groupStack_.pop();
+    }
 
-    this.setNode_(this.group_.firstChild);
+    this.setGroup_(group);
   }
 
 
   /** @private */
   init_() {
+    this.group_.onFocus();
+    this.node_.onFocus();
+
     if (SwitchAccess.get().prefsAreReady()) {
       this.onPrefsReady();
     }
@@ -293,8 +296,7 @@ class NavigationManager {
     this.menuManager_.exit();
 
     this.groupStack_.push(this.group_);
-    this.group_ = group;
-    this.setNode_(this.group_.firstChild);
+    this.setGroup_(group);
   }
 
   /**
@@ -328,11 +330,11 @@ class NavigationManager {
    * @private
    */
   moveToValidNode_() {
-    if (this.node_.role && this.group_.isValid()) {
+    if (this.node_.isValidAndVisible() && this.group_.isValidGroup()) {
       return;
     }
 
-    if (this.node_.role) {
+    if (this.node_.isValidAndVisible()) {
       // Our group has been invalidated. Move to this node to repair the group
       // stack.
       const node = this.node_.automationNode;
@@ -342,7 +344,7 @@ class NavigationManager {
       }
     }
 
-    if (this.group_.isValid()) {
+    if (this.group_.isValidGroup()) {
       const group = this.group_.automationNode;
       if (group) {
         this.moveTo_(group);
@@ -351,7 +353,7 @@ class NavigationManager {
     }
 
     for (let group of this.groupStack_) {
-      if (group.isValid()) {
+      if (group.isValidGroup()) {
         group = group.automationNode;
         if (group) {
           this.moveTo_(group);
@@ -361,11 +363,25 @@ class NavigationManager {
     }
 
     // If there is no valid node in the group stack, go to the desktop.
-    this.group_ = RootNodeWrapper.buildDesktopTree(this.desktop_);
-    this.node_ = this.group_.firstChild;
+    this.setGroup_(RootNodeWrapper.buildDesktopTree(this.desktop_));
     this.groupStack_ = [];
   }
 
+  /**
+   * Set |this.group_| to |group|.
+   * @param {!SARootNode} group
+   * @param {boolean} shouldSetNode
+   */
+  setGroup_(group, shouldSetNode = true) {
+    this.group_.onUnfocus();
+    this.group_ = group;
+    this.group_.onFocus();
+
+    if (shouldSetNode) {
+      this.setNode_(this.group_.firstChild);
+    }
+  }
+
   /**
    * Set |this.node_| to |node|, and update what is displayed onscreen.
    * @param {!SAChildNode} node

chrome/browser/resources/chromeos/accessibility/switch_access/nodes/back_button_node.js

@@ -17,7 +17,7 @@ class BackButtonNode extends SAChildNode {
      */
     this.group_ = group;
 
-    /** @private {chrome.automation.AutomationNode} */
+    /** @private {?chrome.automation.AutomationNode} */
     this.node_ = SwitchAccess.get().getBackButtonAutomationNode();
   }
 
@@ -67,6 +67,11 @@ class BackButtonNode extends SAChildNode {
     return false;
   }
 
+  /** @override */
+  isValidAndVisible() {
+    return this.node_ !== null;
+  }
+
   /** @override */
   onFocus() {
     chrome.accessibilityPrivate.setSwitchAccessMenuState(

chrome/browser/resources/chromeos/accessibility/switch_access/nodes/group_node.js

@@ -89,6 +89,16 @@ class GroupNode extends SAChildNode {
     return true;
   }
 
+  /** @override */
+  isValidAndVisible() {
+    for (const child of this.children_) {
+      if (child.isValidAndVisible()) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   /** @override */
   performAction(action) {
     return true;

chrome/browser/resources/chromeos/accessibility/switch_access/nodes/keyboard_node.js

@@ -106,15 +106,6 @@ class KeyboardRootNode extends RootNodeWrapper {
     chrome.accessibilityPrivate.setVirtualKeyboardVisible(false);
   }
 
-  // ================= Private methods =================
-
-  /**
-   * Custom logic when entering the node.
-   */
-  onEnter_() {
-    chrome.accessibilityPrivate.setVirtualKeyboardVisible(true);
-  }
-
   // ================= Static methods =================
 
   /**
@@ -123,6 +114,8 @@ class KeyboardRootNode extends RootNodeWrapper {
    * @return {!KeyboardRootNode}
    */
   static buildTree(desktop) {
+    KeyboardRootNode.loadKeyboard_();
+
     const keyboardContainer =
         desktop.find({role: chrome.automation.RoleType.KEYBOARD});
     const keyboard =
@@ -134,8 +127,15 @@ class KeyboardRootNode extends RootNodeWrapper {
             .node;
 
     const root = new KeyboardRootNode(keyboard);
-    root.onEnter_();
     KeyboardNode.findAndSetChildren(root);
     return root;
   }
+
+  /**
+   * Loads the keyboard.
+   * @private
+   */
+  static loadKeyboard_() {
+    chrome.accessibilityPrivate.setVirtualKeyboardVisible(true);
+  }
 }

chrome/browser/resources/chromeos/accessibility/switch_access/nodes/node_wrapper.js

@@ -93,6 +93,13 @@ class NodeWrapper extends SAChildNode {
 
   /** @override */
   isEquivalentTo(node) {
+    if (node instanceof NodeWrapper || node instanceof RootNodeWrapper) {
+      return this.baseNode_ === node.baseNode_;
+    }
+
+    if (node instanceof SAChildNode) {
+      return node.isEquivalentTo(this);
+    }
     return this.baseNode_ === node;
   }
 
@@ -101,6 +108,15 @@ class NodeWrapper extends SAChildNode {
     return this.isGroup_;
   }
 
+  /** @override */
+  isValidAndVisible() {
+    // Nodes without a role are not valid.
+    if (!this.baseNode_.role) {
+      return false;
+    }
+    return SwitchAccessPredicate.isVisible(this.baseNode_);
+  }
+
   /** @override */
   performAction(action) {
     let ancestor;
@@ -202,13 +218,20 @@ class RootNodeWrapper extends SARootNode {
   }
 
   /** @override */
-  isEquivalentTo(automationNode) {
-    return this.baseNode_ === automationNode;
+  isEquivalentTo(node) {
+    if (node instanceof RootNodeWrapper || node instanceof NodeWrapper) {
+      return this.baseNode_ === node.baseNode_;
+    }
+
+    if (node instanceof SAChildNode) {
+      return node.isEquivalentTo(this);
+    }
+    return this.baseNode_ === node;
   }
 
   /** @override */
-  isValid() {
-    return !!this.baseNode_.role;
+  isValidGroup() {
+    return !!this.baseNode_.role && super.isValidGroup();
   }
 
   // ================= Static methods =================
@@ -228,8 +251,7 @@ class RootNodeWrapper extends SARootNode {
     }
 
     const childConstructor = (autoNode) => new NodeWrapper(autoNode, root);
-    let children = interestingChildren.map(childConstructor);
-    root.children = children;
+    root.children = interestingChildren.map(childConstructor);
 
     return root;
   }

chrome/browser/resources/chromeos/accessibility/switch_access/nodes/switch_access_node.js

@@ -111,7 +111,7 @@ class SAChildNode {
   }
 
   /**
-   * @param {!chrome.automation.AutomationNode} node
+   * @param {!chrome.automation.AutomationNode|!SAChildNode|!SARootNode} node
    * @return {boolean}
    * @abstract
    */
@@ -124,6 +124,14 @@ class SAChildNode {
    */
   isGroup() {}
 
+  /**
+   * Returns whether this node is still both valid and visible onscreen (e.g.
+   *    not hidden, not offscreen, not invisible)
+   * @return {boolean}
+   * @abstract
+   */
+  isValidAndVisible() {}
+
   /**
    * Called when this node becomes the primary highlighted node.
    */
@@ -259,19 +267,32 @@ class SARootNode {
   }
 
   /**
-   * @param {chrome.automation.AutomationNode} automationNode
+   * @param {chrome.automation.AutomationNode|!SARootNode|!SAChildNode} node
    * @return {boolean}
    */
-  isEquivalentTo(automationNode) {
+  isEquivalentTo(node) {
+    if (node instanceof SARootNode) {
+      return this.equals(node);
+    }
+    if (node instanceof SAChildNode) {
+      return node.isEquivalentTo(this);
+    }
     return false;
   }
 
   /** @return {boolean} */
-  isValid() {
-    return true;
+  isValidGroup() {
+    return this.children_.filter((child) => child.isValidAndVisible()).length >=
+        1;
   }
 
-  /** Called when a group is exiting. */
+  /** Called when a group is set as the current group. */
+  onFocus() {}
+
+  /** Called when a group is no longer the current group. */
+  onUnfocus() {}
+
+  /** Called when a group is explicitly exited. */
   onExit() {}
 
   // ================= Debug methods =================

chrome/browser/resources/chromeos/accessibility/switch_access/switch_access.js

@@ -289,12 +289,13 @@ class SwitchAccess {
     }
   }
 
-  /** @return {chrome.automation.AutomationNode} */
+  /** @return {?chrome.automation.AutomationNode} */
   getBackButtonAutomationNode() {
     if (!this.backButtonAutomationNode_) {
       this.findBackButtonNode_();
       if (!this.backButtonAutomationNode_) {
         console.log('Error: unable to find back button');
+        return null;
       }
     }
     return this.backButtonAutomationNode_;

chrome/browser/resources/chromeos/accessibility/switch_access/switch_access_predicate.js

@@ -13,6 +13,7 @@ const DefaultActionVerb = chrome.automation.DefaultActionVerb;
  *    - isGroup
  *    - isInteresting
  *    - isInterestingSubtree
+ *    - isVisible
  *    - isTextInput
  *    - isNotContainer
  *    - isSwitchAccessMenuPanel
@@ -39,8 +40,7 @@ const SwitchAccessPredicate = {
     const state = node.state;
 
     // Skip things that are offscreen or invisible.
-    if (state[StateType.OFFSCREEN] || !loc || loc.top < 0 || loc.left < 0 ||
-        state[StateType.INVISIBLE]) {
+    if (!SwitchAccessPredicate.isVisible(node)) {
       return false;
     }
 
@@ -145,6 +145,16 @@ const SwitchAccessPredicate = {
   isInteresting: (node, scope) => SwitchAccessPredicate.isActionable(node) ||
       SwitchAccessPredicate.isGroup(node, scope),
 
+  /**
+   * Returns true if the element is visible to the user for any reason.
+   *
+   * @param {chrome.automation.AutomationNode} node
+   * @return {boolean}
+   */
+  isVisible: (node) => !node.state[StateType.OFFSCREEN] && !!node.location &&
+      node.location.top >= 0 && node.location.left >= 0 &&
+      !node.state[StateType.INVISIBLE],
+
   /**
    * Returns true if there is an interesting node in the subtree containing
    * |node| as its root (including |node| itself).