Adds "tts" permission for Input Tools & XKB extension.

chrome/browser/resources/chromeos/input_method/google_xkb_manifest.json

 {
   "name": "Chrome OS XKB",
   "version": "1.0.5.0",
   "description": "Chrome OS XKB",
   "default_locale": "en",
   "incognito": "split",
   "key": "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC7C0oB6YTnf69uhWnVTZl5TB/psHrJXgIPLYchFb0whlVCG8fqMo9lW/oxBmZXZ3N8T7zZrdYI/SUjoc9I5R/dMVVD2q4iKox+x7xlTbqSdVeOb6b9ZVJ24pLbO1L7feSNSBgR0t61jrC2eY/gf78h7w58UEQBPFT2mUxhhwodyQIDAQAB",
   "permissions": [
     "accessibilityFeatures.read",
     "app.window.alpha",
     "app.window.alwaysOnTop",
     "app.window.ime",
     "audioCapture",
     "https://clients4.google.com/",
     "https://dl.google.com/",
     "https://www.googleapis.com/",
     "input",
     "inputMethodPrivate",
     "metricsPrivate",
     "tabs",
+    "tts",
     "unlimitedStorage",
     "virtualKeyboardPrivate"
   ],
   "background": {
     "page": "background.html",
     "persistent": false
   },
   "content_scripts": [
     {
       "matches": ["https://www.googleapis.com/auth/imesync*"],
@@ skipping 630 matching lines @@
       "id": "xkb:mt::mlt",
       "description": "",
       "language": ["mt"],
       "layouts": ["mt"],
       "input_view": "inputview.html#id=mt&language=mt&passwordLayout=mt&name=keyboard_maltese",
       "options_page": "hmm_options.html?code=xkb:mt::mlt"
     }
   ],
   "manifest_version": 2
 }