Move the tts and ttsEngine APIs out of experimental, and give

chrome/test/data/extensions/api_test/tts_engine/register_engine/test.js

Index: chrome/test/data/extensions/api_test/tts_engine/register_engine/test.js
===================================================================
--- chrome/test/data/extensions/api_test/tts_engine/register_engine/test.js	(revision 93167)
+++ chrome/test/data/extensions/api_test/tts_engine/register_engine/test.js	(working copy)
@@ -5,14 +5,6 @@
 // TTS api test for Chrome on ChromeOS.
 // browser_tests.exe --gtest_filter="TtsApiTest.*"
 
-if (!chrome.tts) {
-  chrome.tts = chrome.experimental.tts;
-}
-
-if (!chrome.ttsEngine) {
-  chrome.ttsEngine = chrome.experimental.ttsEngine;
-}
-
 chrome.test.runTests([
   function testNoListeners() {
     // This call should go to native speech because we haven't registered