Add layout tests for ImageLoader::UpdateFromElement(kUpdateForcedReload)

third_party/WebKit/LayoutTests/http/tests/cache/resources/random-cached-image.php

+<?php
+# Returns a cacheable image randomly.

[yhirano, 2017/05/12 10:30:43]

Isn't this comment (and filename) confusing? The tests expect that they get
different images on reload reliably.

[hiroshige, 2017/05/12 17:14:51]

Maybe. I chose the name because this is used similarly to other random-cached*
PHPs.
Updated the comment to describe the current situation, but left the name as-is.
Probably we might want to refactor how to write such tests, but not in this CL.

+
+require_once '../../resources/portabilityLayer.php';
+
+if (!sys_get_temp_dir()) {

[kouhei (in TOK), 2017/05/11 18:22:08]

I'm not sure if we are guaranteed to get same tempdir from sys_get_temp_dir(),
but all other tests seems to rely on this...

+    echo "FAIL: No temp dir was returned.\n";
+    exit();
+}
+
+$id = intval($_GET['id']);
+$countFilename = sys_get_temp_dir() . "/random-cached-image." . $id . ".tmp";
+$count = 0;
+if (file_exists($countFilename)) {
+    $count = file_get_contents($countFilename);
+}
+$count += 1;
+file_put_contents($countFilename, $count);
+
+# Images with different dimensions.
+$imageFilenames = array(
+  '../../resources/square20.png',
+  '../../resources/square100.png',
+  '../../resources/square200.png'
+);
+
+header("Content-type: image/png");
+header("Cache-control: max-age=60000");
+header("ETag: 98765");
+
+readfile($imageFilenames[$count % count($imageFilenames)]);
+?>