Load the Chrome OS TTS engine manifest from the file system isntead of resources.

chrome/common/extensions/extension_constants.cc

Index: chrome/common/extensions/extension_constants.cc
diff --git a/chrome/common/extensions/extension_constants.cc b/chrome/common/extensions/extension_constants.cc
index 341814dbb33fcebd98393d40feb9c79dc8ea0213..3d17c31fe649e20b17f4aaace460cf5dcee25b73 100644
--- a/chrome/common/extensions/extension_constants.cc
+++ b/chrome/common/extensions/extension_constants.cc
@@ -59,8 +59,8 @@ const char kMediaRouterStableExtensionId[] = "fjhoaacokmgbjemoflkofnenfaiekifl";
 const char kChromeVoxExtensionId[] =
     "mndnfokpggljbaajbnioimlmbfngpief";
 const char kChromeVoxExtensionPath[] = "chromeos/chromevox";
-const char kChromeVoxManifestFilename[] = "manifest.json";
-const char kChromeVoxGuestManifestFilename[] = "manifest_guest.json";
+const base::FilePath::CharType kGuestManifestFilename[] =
+    FILE_PATH_LITERAL("manifest_guest.json");
 const char kBrailleImeExtensionId[] =
     "jddehjeebkoimngcbdkaahpobgicbffp";
 const char kBrailleImeExtensionPath[] =