Some fast/table tests should wait for images specified via CSS url()

third_party/WebKit/LayoutTests/fast/table/resources/wait-for-onload.js

Index: third_party/WebKit/LayoutTests/fast/table/resources/wait-for-onload.js
diff --git a/third_party/WebKit/LayoutTests/fast/table/resources/wait-for-onload.js b/third_party/WebKit/LayoutTests/fast/table/resources/wait-for-onload.js
new file mode 100644
index 0000000000000000000000000000000000000000..4afdabc11c106987c99dcf02814bf47929a8d0e6
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/fast/table/resources/wait-for-onload.js
@@ -0,0 +1,15 @@
+if (window.testRunner) {
+  // This is a workaroud for an issue that the test runner sends notifyDone
+  // before resources specified in CSS url finish loading. Currently all
+  // such resources are specified in inline CSSs so we can rely on the
+  // Document load event (Note that we cannot rely on that with linked
+  // CSSs).
+  testRunner.waitUntilDone();
+  window.addEventListener('load', () => {
+    // Force layout.
+    document.body.offsetTop;
+
+    testRunner.notifyDone();
+  });
+}
+