CSSPaint: Move layout tests in csspaint/ to http/tests/csspaint/

third_party/WebKit/LayoutTests/http/tests/resources/run-after-layout-and-paint.js

+// Run a callback after layout and paint of all pending document changes.
+//
+// It has two modes:
+// - traditional mode, for existing tests, and tests needing customized notifyDone timing:
+//   Usage:
+//     if (window.testRunner)
+//       testRunner.waitUntilDone();
+//     runAfterLayoutAndPaint(function() {
+//       ... // some code which modifies style/layout
+//       if (window.testRunner)
+//         testRunner.notifyDone();
+//       // Or to ensure the next paint is executed before the test finishes:
+//       // if (window.testRunner)
+//       //   runAfterAfterLayoutAndPaint(function() { testRunner.notifyDone() });
+//       // Or notifyDone any time later if needed.
+//     });
+//
+// - autoNotifyDone mode, for new tests which just need to change style/layout and finish:
+//   Usage:
+//     runAfterLayoutAndPaint(function() {
+//       ... // some code which modifies style/layout
+//     }, true);
+
+if (window.internals)
+    internals.runtimeFlags.paintUnderInvalidationCheckingEnabled = true;
+
+function runAfterLayoutAndPaint(callback, autoNotifyDone) {
+    if (!window.testRunner) {
+        // For manual test. Delay 500ms to allow us to see the visual change
+        // caused by the callback.
+        setTimeout(callback, 500);
+        return;
+    }
+
+    if (autoNotifyDone)
+        testRunner.waitUntilDone();
+
+    testRunner.layoutAndPaintAsyncThen(function() {
+        callback();
+        if (autoNotifyDone)
+            testRunner.notifyDone();
+    });
+}