Remove willRequestResource callback, it is unused outside of tests.

LayoutTests/fast/dom/HTMLImageElement/image-sizes-js-innerhtml.html

Index: LayoutTests/fast/dom/HTMLImageElement/image-sizes-js-innerhtml.html
diff --git a/LayoutTests/fast/dom/HTMLImageElement/image-sizes-js-innerhtml.html b/LayoutTests/fast/dom/HTMLImageElement/image-sizes-js-innerhtml.html
index a288dff62d51c234c33791a377163d97542a7af5..b6167d805e7793d55e05a5392a8d3b04de8ce0a8 100644
--- a/LayoutTests/fast/dom/HTMLImageElement/image-sizes-js-innerhtml.html
+++ b/LayoutTests/fast/dom/HTMLImageElement/image-sizes-js-innerhtml.html
@@ -6,8 +6,6 @@
         testRunner.dumpAsText();
 
     addEventListener("DOMContentLoaded", function() {
-        if (window.testRunner && sessionStorage.pageReloaded)
-            testRunner.dumpResourceRequestCallbacks();
         window.testdiv = document.createElement("div");
         window.testdiv.innerHTML = '<img id="foo" src="resources/blue-100-px-square.png" srcset="../../hidpi/resources/image-set-1x.png 200w, ../../hidpi/resources/image-set-2x.png 400w, resources/image-set-4x.png 800w">';
     }, false);