Use incognito split for ChromeVox and TTS in Guest mode

chrome/browser/chromeos/accessibility/accessibility_manager.cc

Index: chrome/browser/chromeos/accessibility/accessibility_manager.cc
diff --git a/chrome/browser/chromeos/accessibility/accessibility_manager.cc b/chrome/browser/chromeos/accessibility/accessibility_manager.cc
index 2a23637d92d15c3f11782ff950164ab9d4026448..dc8a6a2d516196db9b5fc2f78538795a7476cd95 100644
--- a/chrome/browser/chromeos/accessibility/accessibility_manager.cc
+++ b/chrome/browser/chromeos/accessibility/accessibility_manager.cc
@@ -157,9 +157,10 @@ void LoadChromeVoxExtension(Profile* profile,
   ExtensionService* extension_service =
       extensions::ExtensionSystem::Get(profile)->extension_service();
   base::FilePath path = GetChromeVoxPath();
+  int idr = profile->IsGuestSession() ?
+      IDR_CHROMEVOX_GUEST_MANIFEST : IDR_CHROMEVOX_MANIFEST;
   std::string extension_id =
-      extension_service->component_loader()->Add(IDR_CHROMEVOX_MANIFEST,
-                                                 path);
+      extension_service->component_loader()->Add(idr, path);
   if (render_view_host) {
     ExtensionService* extension_service =
         extensions::ExtensionSystem::Get(profile)->extension_service();