Add tests for paint-timing, and move existing tests to same location

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

Index: third_party/WebKit/LayoutTests/http/tests/performance-timing/paint-timing/first-paint-only.html
diff --git a/third_party/WebKit/LayoutTests/fast/performance/performance-first-paint-timing-observable.html b/third_party/WebKit/LayoutTests/http/tests/performance-timing/paint-timing/first-paint-only.html
similarity index 92%
rename from third_party/WebKit/LayoutTests/fast/performance/performance-first-paint-timing-observable.html
rename to third_party/WebKit/LayoutTests/http/tests/performance-timing/paint-timing/first-paint-only.html
index 081aeb32005712254a85941fab742c9930d854c4..77160b816e305e156d5ebd1e5e07175c0aec446d 100644
--- a/third_party/WebKit/LayoutTests/fast/performance/performance-first-paint-timing-observable.html
+++ b/third_party/WebKit/LayoutTests/http/tests/performance-timing/paint-timing/first-paint-only.html
@@ -26,7 +26,7 @@
         );
         observer.observe({entryTypes: ["paint"]});
 
-    }, "Performance first paint timing entry is observable.");
+    }, "Performance first paint timing entry is observable. No first contentful paint.");

[igrigorik, 2017/05/08 20:37:04]

Does it make sense to t.done() after onload? 

[panicker, 2017/05/09 17:55:06]

Good point, I added a step_timeout to wait for 1s before wrapping up.

     </script>
     
     <div style="background-color:black;color:white;padding:20px;"></div>