Move socket API from experimental to dev channel and remove some dead code

chrome/test/data/extensions/api_test/socket/api/background.js

Index: chrome/test/data/extensions/api_test/socket/api/background.js
diff --git a/chrome/test/data/extensions/api_test/socket/api/background.js b/chrome/test/data/extensions/api_test/socket/api/background.js
index 09e74dd4be7e79dc368a0f2cfbc7f1b8539730d9..78d47f431e99c359698c6acce336b35bc975b44e 100644
--- a/chrome/test/data/extensions/api_test/socket/api/background.js
+++ b/chrome/test/data/extensions/api_test/socket/api/background.js
@@ -10,7 +10,7 @@
 const request = "0100000005320000005hello";
 var expectedResponsePattern = /0100000005320000005.{11}/;
 
-const socket = chrome.experimental.socket;
+const socket = chrome.socket;
 var address;
 var bytesWritten = 0;
 var dataAsString;