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..343fa4a1213ade96fc1062dab763870912328fb9 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
@@ -26,9 +26,9 @@
         );
         observer.observe({entryTypes: ["paint"]});
 
-    }, "Performance first paint timing entry is observable.");
+    }, "Performance first paint timing entry is observable. No first contentful paint.");
     </script>
-    
+
     <div style="background-color:black;color:white;padding:20px;"></div>
 </body>
 </html>