[Resource Timing] Expose redirect timing information

LayoutTests/http/tests/w3c/webperf/resources/multi_redirect.php

Index: LayoutTests/http/tests/w3c/webperf/resources/multi_redirect.php
diff --git a/LayoutTests/http/tests/w3c/webperf/resources/multi_redirect.php b/LayoutTests/http/tests/w3c/webperf/resources/multi_redirect.php
new file mode 100644
index 0000000000000000000000000000000000000000..b9468f13425fbf7ccdbb408d0eeac360d8ddf1cd
--- /dev/null
+++ b/LayoutTests/http/tests/w3c/webperf/resources/multi_redirect.php
@@ -0,0 +1,31 @@
+<?php
+  $step = $_GET["step"] ? $_GET["step"] : 1;
+  $pageOrigin = $_GET["pageOrigin"];
+  $crossOrigin = $_GET["crossOrigin"];
+  $timingAllow = $_GET["timingAllow"] ? $_GET["timingAllow"] : 0;
+  $redirectURL = "/w3c/webperf/resources/multi_redirect.php?pageOrigin=$pageOrigin&crossOrigin=$crossOrigin&timingAllow=$timingAllow";
+
+  switch ($step) {
+    case 1:
+      $redirectURL = $crossOrigin . $redirectURL . "&step=2";
+      if ($timingAllow != "0")
+        header("timing-allow-origin: $pageOrigin");
+      break;
+    case 2:
+      $redirectURL = $pageOrigin . $redirectURL . "&step=3";
+      if ($timingAllow != "0")
+        header("timing-allow-origin: $pageOrigin");
+      break;
+    case 3:
+      $redirectURL = $pageOrigin . "/w3c/webperf/resources/blank_page_green.htm";
+
+      break;
+    default:
+      break;
+  }
+
+  header("HTTP/1.1 302");
+  header("Location: $redirectURL");
+  sleep(1);
+  exit;
+?>