Add a warning for the deprecation of content-initiated data URL navigations

third_party/WebKit/LayoutTests/fast/events/pageshow-pagehide-on-back-uncached.html

 <p>Test pageshow/pagehide event behavior when navigating back to an uncached page.</p>
 <script>
 if (window.testRunner) {
     testRunner.dumpAsText();
     testRunner.waitUntilDone();
 }
 
 window.onload = function(evt) {
     alert("window.onload");
     if (window.name == 'pageshow/pagehide') {
         // Returned back.
         window.name = "";
         window.onpagehide = null;
         setTimeout(function() { if (window.testRunner) testRunner.notifyDone(); }, 10);
     } else {
         window.name = "pageshow/pagehide";
-        setTimeout('window.location = "data:text/html,<script>history.back();</scr" + "ipt>"', 0);
+        setTimeout('window.location = "../../resources/back.html"', 0);
     }
 }
 
 window.onunload = function() {}  // prevent caching
 
 window.onpageshow = function(evt) {
     alert("window.onpageshow" + ", target = " + evt.target + ", persisted = " + evt.persisted);
 }
 
 window.onpagehide = function(evt) {
     alert("window.onpagehide" + ", target = " + evt.target + ", persisted = " + evt.persisted);
 }
 
 </script>