[M103] [ChromeVox] Include PanelBridge in background context

This change fixes a bug where PanelBridge was never actually imported.

(cherry picked from commit c9fe657)

AX-Relnotes: n/a.
Bug: 1330462,1329191
Fixed: 1330992
Change-Id: Ic91b908942ad67f30e83783f06b7fbd9d0611e27
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3682176
Commit-Queue: Anastasia Helfinstein <anastasi@google.com>
Reviewed-by: David Tseng <dtseng@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1009805}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3688329
Reviewed-by: Akihiro Ota <akihiroota@chromium.org>
Auto-Submit: Anastasia Helfinstein <anastasi@google.com>
Commit-Queue: Akihiro Ota <akihiroota@chromium.org>
Cr-Commit-Position: refs/branch-heads/5060@{#497}
Cr-Branched-From: b83393d-refs/heads/main@{#1002911}

chrome/browser/resources/chromeos/accessibility/chromevox/BUILD.gn

@@ -60,6 +60,7 @@ chromevox_modules = [
   "common/locale_output_helper.js",
   "common/log_types.js",
   "common/msgs.js",
+  "common/panel_bridge.js",
   "common/panel_command.js",
   "common/panel_menu_data.js",
   "common/spannable.js",

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

@@ -35,6 +35,7 @@ goog.require('Msgs');
 goog.require('NavBraille');
 goog.require('Output');
 goog.require('OutputEventType');
+goog.require('PanelBridge');
 goog.require('PanelCommand');
 goog.require('PanelNodeMenuData');
 goog.require('PanelTabMenuItemData');