Don't fire popstate event on initial document load

LayoutTests/http/tests/history/popstate-fires-with-pending-requests.html

Index: LayoutTests/http/tests/history/popstate-fires-with-pending-requests.html
diff --git a/LayoutTests/http/tests/history/popstate-fires-with-pending-requests.html b/LayoutTests/http/tests/history/popstate-fires-with-pending-requests.html
index 0e09038d5c1d96fba6c75d48355424f3581eabf8..441dd8841aec4109903be2e9d8f3b0c37ca197c2 100644
--- a/LayoutTests/http/tests/history/popstate-fires-with-pending-requests.html
+++ b/LayoutTests/http/tests/history/popstate-fires-with-pending-requests.html
@@ -10,29 +10,20 @@
 <script>
 description('Tests that popstate events fire when going back, even when there are resource requests pending.');
 
-onpopstate = function(event)
+window.onload = function()
 {
-    if (event.state) {
-        shouldBe('event.state', '"newState1"');
-        // Stop the pending image request, otherwise the DRT doesn't consider the
-        // test over.
-        window.stop();
-        finishJSTest();
-        return;
-    }
-    
     debug('Starting slow image request');
-      
+
     var slowImage = document.createElement('img');
     slowImage.src = 'resources/slow-image.php';
     document.body.appendChild(slowImage);
-    
+
     debug('Pushing newState1');
     history.pushState('newState1', null, '?newState1');
-    
+
     setTimeout(function() {
         debug('Current search: ' + location.search);
-    
+
         debug('Pushing newState2');
         history.pushState('newState2', null, '?newState2');
         setTimeout(function() {
@@ -43,9 +34,17 @@ onpopstate = function(event)
     }, 0);
 }
 
+window.onpopstate = function(event)
+{
+    shouldBe('event.state', '"newState1"');
+    // Stop the pending image request, otherwise the DRT doesn't consider the
+    // test over.
+    window.stop();
+    finishJSTest();
+}
 
 var jsTestIsAsync = true;
-</script> 
+</script>
 
 </body>
 </html>