Recover ChromeVox range to last hover target for navigation gestures

R=dmazzoni@chromium.org

Change-Id: I78f5c5274ef665b844e4f85648a77b74f9b953de
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2157991Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: David Tseng <dtseng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#760998}

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

@@ -57,6 +57,9 @@ DesktopAutomationHandler = class extends BaseAutomationHandler {
     /** @private {!Date} */
     this.lastHoverExit_ = new Date();
 
+    /** @private {!AutomationNode|undefined} */
+    this.lastHoverTarget_;
+
     this.addListener_(EventType.ALERT, this.onAlert);
     this.addListener_(EventType.BLUR, this.onBlur);
     this.addListener_(
@@ -96,6 +99,14 @@ DesktopAutomationHandler = class extends BaseAutomationHandler {
     return this.textEditHandler_;
   }
 
+  /**
+   * @return {!AutomationNode|undefined} The target of the last observed hover
+   *     event.
+   */
+  get lastHoverTarget() {
+    return this.lastHoverTarget_;
+  }
+
   /** @override */
   willHandleEvent_(evt) {
     return false;
@@ -152,6 +163,9 @@ DesktopAutomationHandler = class extends BaseAutomationHandler {
 
     EventSourceState.set(EventSourceType.TOUCH_GESTURE);
 
+    // Save the last hover target for use by the gesture handler.
+    this.lastHoverTarget_ = evt.target;
+
     let target = evt.target;
     let targetLeaf = null;
     let targetObject = null;

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

@@ -14,7 +14,8 @@ goog.provide('GestureGranularity');
  *     command: string,
  *     menuKeyOverride: (boolean|undefined),
  *     keyOverride: ({keyCode: number, modifiers: ({ctrl:
- * boolean}|undefined)}|undefined)
+ * boolean}|undefined)}|undefined),
+ *     shouldRecoverRange: (boolean|undefined)
  *    }>}
  * @const
  */
@@ -24,25 +25,29 @@ GestureCommandData.GESTURE_COMMAND_MAP = {
     msgId: 'swipeUp1_gesture',
     command: 'previousAtGranularity',
     menuKeyOverride: true,
-    keyOverride: {keyCode: 38 /* up */, skipStart: true, multiline: true}
+    keyOverride: {keyCode: 38 /* up */, skipStart: true, multiline: true},
+    shouldRecoverRange: true
   },
   'swipeDown1': {
     msgId: 'swipeDown1_gesture',
     command: 'nextAtGranularity',
     menuKeyOverride: true,
-    keyOverride: {keyCode: 40 /* Down */, skipEnd: true, multiline: true}
+    keyOverride: {keyCode: 40 /* Down */, skipEnd: true, multiline: true},
+    shouldRecoverRange: true
   },
   'swipeLeft1': {
     msgId: 'swipeLeft1_gesture',
     command: 'previousObject',
     menuKeyOverride: true,
-    keyOverride: {keyCode: 37 /* left */}
+    keyOverride: {keyCode: 37 /* left */},
+    shouldRecoverRange: true
   },
   'swipeRight1': {
     msgId: 'swipeRight1_gesture',
     command: 'nextObject',
     menuKeyOverride: true,
-    keyOverride: {keyCode: 39 /* right */}
+    keyOverride: {keyCode: 39 /* right */},
+    shouldRecoverRange: true
   },
   'swipeUp2': {msgId: 'swipeUp2_gesture', command: 'jumpToTop'},
   'swipeDown2': {msgId: 'swipeDown2_gesture', command: 'readFromHere'},

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

@@ -76,6 +76,14 @@ GestureCommandHandler.onAccessibilityGesture_ = function(gesture) {
     }
   }
 
+  if (!ChromeVoxState.instance.currentRange && commandData.shouldRecoverRange) {
+    const recoverTo = DesktopAutomationHandler.instance.lastHoverTarget;
+    if (recoverTo) {
+      ChromeVoxState.instance.setCurrentRange(
+          cursors.Range.fromNode(recoverTo));
+    }
+  }
+
   const command = commandData.command;
   if (command) {
     CommandHandler.onCommand(command);