remove cookie expiration and add max-age of 2 years.
bug: 17781603

Change-Id: Idab3cae786fde4d0318ba03d3c7f5f678882b815
(cherry picked from commit f51f30d7f10a32e07a081b799d9ae601be08276c)
diff --git a/tools/droiddoc/templates-sdk/assets/js/docs.js b/tools/droiddoc/templates-sdk/assets/js/docs.js
index d3f815a..8daef7f 100644
--- a/tools/droiddoc/templates-sdk/assets/js/docs.js
+++ b/tools/droiddoc/templates-sdk/assets/js/docs.js
@@ -900,16 +900,14 @@
   return 0;
 }
 
-function writeCookie(cookie, val, section, expiration) {
+function writeCookie(cookie, val, section, age) {
   if (val==undefined) return;
   section = section == null ? "_" : "_"+section+"_";
-  if (expiration == null) {
-    var date = new Date();
-    date.setTime(date.getTime()+(10*365*24*60*60*1000)); // default expiration is one week
-    expiration = date.toGMTString();
+  if (age == null) {
+    var age = 2*365*24*60*60; // set max-age to 2 years
   }
   var cookieValue = cookie_namespace + section + cookie + "=" + val
-                    + "; expires=" + expiration+"; path=/";
+                    + "; max-age=" + age +"; path=/";
   document.cookie = cookieValue;
 }