Update PaintTiming Web Perf APIs for FP & FCP to report swap time

third_party/WebKit/LayoutTests/http/tests/performance-timing/paint-timing/observable.html

Index: third_party/WebKit/LayoutTests/http/tests/performance-timing/paint-timing/observable.html
diff --git a/third_party/WebKit/LayoutTests/http/tests/performance-timing/paint-timing/observable.html b/third_party/WebKit/LayoutTests/http/tests/performance-timing/paint-timing/observable.html
index ad7272486be65ee9caa7afaaca137a7adc126335..20b55a1ff5f1cf6ce8ca9612fdb4bf57664e0692 100644
--- a/third_party/WebKit/LayoutTests/http/tests/performance-timing/paint-timing/observable.html
+++ b/third_party/WebKit/LayoutTests/http/tests/performance-timing/paint-timing/observable.html
@@ -48,6 +48,10 @@
 
     }, "Both first-paint-timing and first-contentful-paint timing entry are observable.");
 
+    if (window.testRunner) {
+        testRunner.waitUntilDone();
+        testRunner.capturePixelsAsyncThen(async_test);
+    }
     </script>
     <div style="background-color:black;color:white;padding:20px;">...test...</div>
 </body>