Adds experimental flag --enable-experimental-ime-features.

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

 {
   "key": "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDyRb75ZzKuseD4ZEposVSGTJQjdySVjVA0s2hgFYDJ3hRh5wATyWsLL7EYvbfi2K+hbYBvrxOQYot4eArQloShy4tdQTZovmTXIINIOzN3j/avFfrYSnJNV6C6gpGKglGVEw/lhf+6WdSnGoWjqXWQnnJltc2JtiAk51nkFJUWZwIDAQAB",
   "name": "__MSG_chos_inputtool_title__",
   "version": "4.3.2.3",
   "description": "The Google Input Tools",
   "default_locale": "en",
   "incognito": "split",
   "permissions": [
     "input",
     "unlimitedStorage",
@@ skipping 266 matching lines @@
     {
       "name": "__MSG_transliteration_ur__",
       "type": "ime",
       "id": "ur-t-i0-und",
       "description": "Urdu",
       "language": "ur",
       "layouts": ["us"],
       "input_view": "inputview.html#id=t13n-rtl&language=ur&passwordLayout=t13n-rtl&name=transliteration_ur"
     },
     {
+      "name": "__MSG_inputmethod_hangul__",
+      "type": "ime",
+      "id": "ko-t-i0-und",
+      "indicator": "\uD55C",
+      "description": "Korean input method.",
+      "language": "ko",
+      "layouts": ["us"],
+      "input_view": "inputview.html#id=m17n:ko_2set&language=ko&passwordLayout=us&name=inputmethod_hangul",
+      "options_page": "hmm_options.html?code=ko-t-i0-und"
+    },
+    {
       "name": "__MSG_inputmethod_mozc_us__",
       "type": "ime",
       "id": "nacl_mozc_us",
       "indicator": "\u3042",
       "description": "Japanese input method.",
       "language": "ja",
       "layouts": ["us"],
       "input_view": "inputview.html#id=jp_us&language=ja&passwordLayout=us&name=appNameUSKeyboard",
       "options_page": "mozc_option.html"
     },
@@ skipping 292 matching lines @@
       "type": "ime",
       "id": "vkd_ru_phone_yazhert",
       "description": "",
       "language": ["ru"],
       "layouts": ["us"],
       "input_view": "inputview.html#id=m17n:ru_phone_yazhert&language=ru&passwordLayout=us&name=keyboard_russian_phonetic_yazhert"
     }
   ],
   "manifest_version": 2
 }