Revert of Remove EventSender from ImageLoader

third_party/WebKit/LayoutTests/http/tests/resources/srcset-helper.js

 function runTest() {
     if (!window.testRunner || !window.sessionStorage)
         return;
 
     if (!window.targetScaleFactor)
         window.targetScaleFactor = 2;
 
     if (!sessionStorage.scaleFactorIsSet) {
         testRunner.waitUntilDone();
         testRunner.setBackingScaleFactor(targetScaleFactor, scaleFactorIsSet);
     }
 
     if (sessionStorage.pageReloaded && sessionStorage.scaleFactorIsSet) {
         delete sessionStorage.pageReloaded;
         delete sessionStorage.scaleFactorIsSet;
         if (!window.manualNotifyDone) {
             setTimeout(function() {
                 testRunner.notifyDone();
             }, 0);
         }
     } else {
         // Right now there is a bug that srcset does not properly deal with dynamic changes to the scale factor,
         // so to work around that, we must reload the page to get the new image.
-        //
-        // At the time of the Document load event, there might be other
-        // ongoing tasks that can cause new images to be loaded. To evict
-        // those images, we delay evictAllResources() call a little.
-        setTimeout(function() {
-          sessionStorage.pageReloaded = true;
-          if (window.internals) {
-              internals.evictAllResources();
-          }
-          document.location.reload(true);
-        }, 300);
+        sessionStorage.pageReloaded = true;
+        if (window.internals) {
+            internals.evictAllResources();
+        }
+        document.location.reload(true);
     }
 }
 
 function scaleFactorIsSet() {
     sessionStorage.scaleFactorIsSet = true;
 }
 
 window.addEventListener("load", runTest, false);