Remove left-over PageCache stuff

LayoutTests/fast/images/animated-gif-restored-from-bfcache.html

-<script>
-    if (window.testRunner) {
-        testRunner.dumpAsText();
-        testRunner.overridePreference("WebKitUsesPageCachePreferenceKey", 1);
-    }
-
-    function runTest() {
-        if (window.testRunner)
-            testRunner.waitUntilDone();
-
-        var image = document.getElementById("image");
-        var console = document.getElementById("console");            
-        var context = document.getElementById("canvas").getContext("2d");
-
-        image.style.visibility = "visible";
-
-        context.drawImage(image, 0, 0);
-        var frameOne = context.getImageData(0, 0, 1, 1).data;
-
-        window.setTimeout(function() {
-            context.drawImage(image, 0, 0);
-            var frameTwo = context.getImageData(0, 0, 1, 1).data;
-
-            // Compare RGBA of the two frames
-            if (frameOne[0] == frameTwo[0]
-                && frameOne[1] == frameTwo[1]
-                && frameOne[2] == frameTwo[2]
-                && frameOne[3] == frameTwo[3])
-                console.innerHTML = "<span style='color:red'>FAIL</span>";
-            else
-                console.innerHTML = "<span style='color:green'>PASS</span>";
-
-            if (window.testRunner)
-                testRunner.notifyDone();
-        }, 100);
-    }
-
-    window.onpageshow = function(event) {
-        if (!event.persisted && window.testRunner) {
-            testRunner.queueLoad("about:blank");
-            testRunner.queueBackNavigation(1);
-            return;
-        }
-
-        if (event.persisted)
-            runTest();
-    }
-</script>
-<p>Test that animated GIFs resume animating after restoring a page from the back forward cache. To test manually, click <a href="about:blank">here</a> to visit about:blank, then press the browser's back button. On success, you should see a square that continuously animates through various shades of green followed by the word 'PASS'.</p>
-<img id="image" style="visibility:hidden" src="resources/animated-10color.gif">
-<div id="console"></div>
-<canvas id="canvas" style="visibility:hidden"><span style="color:red">FAIL</span></canvas>