Add ImageLoader support for sizes based Client-Hints RW values

LayoutTests/http/tests/misc/client-hints-dynamic-rw-sizes.html

Index: LayoutTests/http/tests/misc/client-hints-dynamic-rw-sizes.html
diff --git a/LayoutTests/http/tests/misc/client-hints-preload-rw-sizes.html b/LayoutTests/http/tests/misc/client-hints-dynamic-rw-sizes.html
similarity index 61%
copy from LayoutTests/http/tests/misc/client-hints-preload-rw-sizes.html
copy to LayoutTests/http/tests/misc/client-hints-dynamic-rw-sizes.html
index fdd70821515f37678548bb3f1cde8dfaa0b3b1b7..8e01f8ea2c41ea438c440598574bf142af732e9e 100644
--- a/LayoutTests/http/tests/misc/client-hints-preload-rw-sizes.html
+++ b/LayoutTests/http/tests/misc/client-hints-dynamic-rw-sizes.html
@@ -2,12 +2,11 @@
 <meta http-equiv="Accept-CH" content="DPR, RW">
 <script src="../resources/testharness.js"></script>
 <script src="../resources/testharnessreport.js"></script>
-<script src="../resources/slow-script.pl?delay=300"></script>
-<img id="testimg1" src="resources/image-checks-for-rw.php?rw=480" sizes="60vw">
-<img id="testimg2" sizes="40vw" src="resources/image-checks-for-rw.php?rw=320" sizes="60vw">
-<img id="testimg3" sizes="50vw" src="resources/image-checks-for-rw.php?rw=400">
 <script>
-    var t = async_test('Client-Hints sent with the right RW value Accept-CH header is present');
+    document.write('<img id="testimg1" src="resources/image-checks-for-rw.php?rw=480" sizes="60vw">');
+    document.write('<img id="testimg2" sizes="40vw" src="resources/image-checks-for-rw.php?rw=320" sizes="60vw">');
+    document.write('<img id="testimg3" sizes="50vw" src="resources/image-checks-for-rw.php?rw=400">');
+    var t = async_test('Client-Hints sent with the right RW value when Accept-CH header is present');
     window.onload = t.step_func(function() {
         assert_not_equals(document.getElementById("testimg1").naturalWidth, 0);
         assert_not_equals(document.getElementById("testimg2").naturalWidth, 0);