Add cursor routing to the braille caption panel in Chromevox.

When a user clicks on a character in the braille caption panel, it
sends a routing event to the braille command listener and moves
the cursor to the designated position.

Chromevox. Click on a character in the panel to move the cursor to the
desired position.

AX-Relnotes: Added cursor routing to the braille caption panel in
Change-Id: I28e10e17f81c9b0336842a2756263c9f5acb8df2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2333752Reviewed-by: David Tseng <dtseng@chromium.org>
Commit-Queue: Abigail Klein <abigailbklein@google.com>
Cr-Commit-Position: refs/heads/master@{#795933}

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

@@ -126,6 +126,11 @@ BrailleBackground = class {
     this.displayManager_.panRight();
   }
 
+  /** @override */
+  route(displayPosition) {
+    return this.displayManager_.route(displayPosition);
+  }
+
   /**
    * @param {!NavBraille} newContent
    * @param {?string} newContentId

chrome/browser/resources/chromeos/accessibility/chromevox/braille/braille_display_manager.js

@@ -388,11 +388,8 @@ BrailleDisplayManager = class {
         this.panRight();
         break;
       case BrailleKeyCommand.ROUTING:
-        event.displayPosition = this.brailleToTextPosition_(
-            event.displayPosition +
-            this.panStrategy_.viewPort.firstRow *
-                this.panStrategy_.displaySize.columns);
-      // fall through
+        this.route(event.displayPosition);
+        break;
       default:
         this.commandListener_(event, this.content_);
         break;
@@ -427,6 +424,24 @@ BrailleDisplayManager = class {
     }
   }
 
+  /**
+   * Moves the cursor to the given braille position.
+   * @param {number|undefined} braillePosition The 0-based position relative to
+   *     the start of the currently displayed text. The position is given in
+   *     braille cells, not text cells.
+   */
+  route(braillePosition) {
+    if (braillePosition == undefined) {
+      return;
+    }
+    const displayPosition = this.brailleToTextPosition_(
+        braillePosition +
+        this.panStrategy_.viewPort.firstRow *
+            this.panStrategy_.displaySize.columns);
+    this.commandListener_(
+        {command: BrailleKeyCommand.ROUTING, displayPosition}, this.content_);
+  }
+
   /**
    * Sets a cursor within translated content.
    * @param {ArrayBuffer} buffer Buffer to add cursor to.

chrome/browser/resources/chromeos/accessibility/chromevox/common/braille_interface.js

@@ -58,4 +58,12 @@ BrailleInterface = class {
    * Requests the braille display pan right.
    */
   panRight() {}
+
+  /**
+   * Moves the cursor to the given braille position.
+   * @param {number|undefined} braillePosition The 0-based position relative to
+   *     the start of the currently displayed text. The position is given in
+   *     braille cells, not text cells.
+   */
+  route(braillePosition) {}
 };

chrome/browser/resources/chromeos/accessibility/chromevox/panel/panel.js

@@ -660,8 +660,24 @@ Panel = class {
       }
     };
 
+    const routeCursor = function(event) {
+      const cell = event.target;
+      if (cell.tagName == 'TD') {
+        const displayPosition = parseInt(cell.id.split('-')[0], 10);
+        if (Number.isNaN(displayPosition)) {
+          throw new Error(
+              'The display position is calculated assuming that the cell ID ' +
+              'is formatted like int-string. For example, 0-brailleCell is a ' +
+              'valid cell ID.');
+        }
+        chrome.extension.getBackgroundPage()['ChromeVox'].braille.route(
+            displayPosition);
+      }
+    };
+
     Panel.brailleContainer_.addEventListener('mouseover', addBorders);
     Panel.brailleContainer_.addEventListener('mouseout', removeBorders);
+    Panel.brailleContainer_.addEventListener('click', routeCursor);
 
     // Clear the tables.
     let rowCount = Panel.brailleTableElement_.rows.length;