Support a private event - inputMethodPrivate.onCompositionBoundsChanged so that component IME exten…

chrome/common/extensions/api/input_method_private.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": "inputMethodPrivate",
     "platforms": ["chromeos"],
     "description": "none",
     "functions": [
@@ skipping 91 matching lines @@
         "name": "onChanged",
         "type": "function",
         "description": "Fired when the input method is changed.",
         "parameters": [
           {
             "name": "newInputMethodId",
             "type": "string",
             "description": "New input method which is being used."
           }
         ]
+      }, {
+        "name": "onCompositionBoundsChanged",
+        "type": "function",
+        "description": "Fired when the composition bounds are changed.",
+        "parameters": [
+          {
+            "name": "bounds",
+            "type": "object",
+            "description": "Composition bounds.",
+            "properties": {
+              "x": {"type": "integer"},
+              "y": {"type": "integer"},
+              "w": {"type": "integer"},
+              "h": {"type": "integer"}
+            }
+          }
+        ]
       }
     ]
   }
 ]