[Switch Access] Move cut/copy/paste implementations into node

This is a step towards incorporating Rose and Sophie's code (see links
below) for text navigation and selection from last summer into the
new navigation paradigm.

Ex: https://chromium-review.googlesource.com/c/chromium/src/+/1772301
https://chromium-review.googlesource.com/c/chromium/src/+/1727242

Bug: 982004
Change-Id: I9a3c9e86dfdf15c3cdaea0086f64273192c06491
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2076445
Commit-Queue: Anastasia Helfinstein <anastasi@google.com>
Reviewed-by: Nektarios Paisios <nektar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#746625}

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

@@ -519,15 +519,6 @@ class MenuManager {
       case SAConstants.MenuAction.MOVE_UP_ONE_LINE_OF_TEXT:
         TextNavigationManager.moveUpOneLine();
         return;
-      case SAConstants.MenuAction.CUT:
-        EventHelper.simulateKeyPress(EventHelper.KeyCode.X, {ctrl: true});
-        return;
-      case SAConstants.MenuAction.COPY:
-        EventHelper.simulateKeyPress(EventHelper.KeyCode.C, {ctrl: true});
-        return;
-      case SAConstants.MenuAction.PASTE:
-        EventHelper.simulateKeyPress(EventHelper.KeyCode.V, {ctrl: true});
-        return;
       case SAConstants.MenuAction.SELECT_START:
         TextNavigationManager.saveSelectStart();
         if (this.menuOriginNode_) {

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

@@ -60,6 +60,15 @@ class EditableTextNode extends NodeWrapper {
       case SAConstants.MenuAction.DICTATION:
         chrome.accessibilityPrivate.toggleDictation();
         return SAConstants.ActionResponse.CLOSE_MENU;
+      case SAConstants.MenuAction.CUT:
+        EventHelper.simulateKeyPress(EventHelper.KeyCode.X, {ctrl: true});
+        return SAConstants.ActionResponse.REMAIN_OPEN;
+      case SAConstants.MenuAction.COPY:
+        EventHelper.simulateKeyPress(EventHelper.KeyCode.C, {ctrl: true});
+        return SAConstants.ActionResponse.REMAIN_OPEN;
+      case SAConstants.MenuAction.PASTE:
+        EventHelper.simulateKeyPress(EventHelper.KeyCode.V, {ctrl: true});
+        return SAConstants.ActionResponse.REMAIN_OPEN;
     }
     return super.performAction(action);
   }