Implement input.ime.sendKeyEvents API.

chrome/test/data/extensions/api_test/input_ime_nonchromeos/background.js

 // Copyright 2016 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.
 
 chrome.test.runTests([
   function testActivate() {
     var focused = false;
     var activated = false;
     chrome.input.ime.onFocus.addListener(function(context) {
       if (context.type == 'none') {
@@ skipping 34 matching lines @@
       chrome.test.assertNoLastError()
       chrome.test.assertTrue(!!win);
       chrome.test.assertTrue(win instanceof Window);
       chrome.test.assertFalse(win.document.webkitHidden);
       // test for security origin.
       // If security origin is not correctly set, there will be securtiy
       // exceptions when accessing DOM or add event listeners.
       win.addEventListener('unload', function() {});
       chrome.test.succeed();
     });
+  },
+
+  function testSendKeyEvents() {
+    chrome.input.ime.sendKeyEvents({
+      'contextID': 1,
+      'keyData': [{
+        'type': 'keydown',
+        'requestId': '0',
+        'key': 'a',
+        'code': 'KeyA'
+      }, {
+        'type': 'keyup',
+        'requestId': '1',
+        'key': 'a',
+        'code': 'KeyA'
+     }]
+    });
+    chrome.test.succeed();
   }
 ]);