Support invisible underline for IME composition.

chrome/common/extensions/api/input_ime.json

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 [
   {
     "namespace": "input.ime",
     "description": "Use the <code>chrome.input.ime</code> API to implement a custom IME for Chrome OS. This allows your extension to handle keystrokes, set the composition, and manage the candidate window.",
     "platforms": ["chromeos"],
     "types": [
@@ skipping 83 matching lines @@
                   "properties": {
                     "start": {
                       "description": "Index of the character to start this segment at",
                       "type": "integer"
                     },
                     "end": {
                       "description": "Index of the character to end this segment after.",
                       "type": "integer"
                     },
                     "style": {
                       "description": "How to render this segment",

[Seigo Nonaka, 2014/10/13 06:23:10]

nit: I'm sorry this is not your fault but let's change this unclear description
to more "underline" specific one.

How about "The type of the underline to modify this segment."

[Shu Chen, 2014/10/13 06:28:11]

Done.

-                      "enum": ["underline", "doubleUnderline"],
+                      "enum": ["underline", "doubleUnderline", "noUnderline"],
                       "type": "string"
                     }
                   }
                 }
               }
             }
           },
           {
             "type": "function",
             "name": "callback",
@@ skipping 557 matching lines @@
           {
             "type": "string",
             "name": "engineID",
             "description": "ID of the engine receiving the event"
           }
         ]
       }
     ]
   }
 ]