Reland of HTMLImageElement: do not use fallback content for ImageDocument

third_party/WebKit/LayoutTests/http/tests/images/png-partial-load-as-document.html

Index: third_party/WebKit/LayoutTests/http/tests/images/png-partial-load-as-document.html
diff --git a/third_party/WebKit/LayoutTests/http/tests/images/png-partial-load-as-document.html b/third_party/WebKit/LayoutTests/http/tests/images/png-partial-load-as-document.html
new file mode 100644
index 0000000000000000000000000000000000000000..1b37ce263bbde75186227a903f67d11ae72fdbd5
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/http/tests/images/png-partial-load-as-document.html
@@ -0,0 +1,40 @@
+<iframe style="background-color: blue; width: 320px; height: 240px;"></iframe>
+<!--
+Tests that when a progressive png is loaded as document, the image is shown
+progressively during loading.
+The result image should show the dice image partially.
+-->
+<script>
+if (window.testRunner) {
+    testRunner.dumpAsTextWithPixelResults();
+    testRunner.waitUntilDone();
+}
+
+function loadAndStall()
+{
+    return "http://127.0.0.1:8000/resources/load-and-stall.php";
+}
+
+function pngImage()
+{
+    return "?name=../../../fast/images/resources/dice.png&mimeType=image%2Fpng";
+}
+
+function testDone()
+{
+    if (window.testRunner) {
+        window.stop();
+        testRunner.notifyDone();
+    }
+}
+
+function runTest()
+{
+    document.querySelector("iframe").src = loadAndStall() + pngImage() + "&stallAt=45057&stallFor=60";
+    setTimeout(testDone, 500);
+}
+
+window.onload = function() {
+    setTimeout(runTest, 0);
+}
+</script>