[Bindings] Create and use V8 context snapshots

third_party/WebKit/LayoutTests/SlowTests

Index: third_party/WebKit/LayoutTests/SlowTests
diff --git a/third_party/WebKit/LayoutTests/SlowTests b/third_party/WebKit/LayoutTests/SlowTests
index a08b1ed1d4636831e36afe69f4aaf253027a9b54..be78bffa48849e6e4eb5459669d0a384a579b164 100644
--- a/third_party/WebKit/LayoutTests/SlowTests
+++ b/third_party/WebKit/LayoutTests/SlowTests
@@ -397,3 +397,9 @@ crbug.com/451577 [ Linux ] inspector/layers/layer-canvas-log.html [ Slow ]
 crbug.com/736056 external/wpt/encoding/legacy-mb-japanese [ Slow ]
 crbug.com/736056 external/wpt/encoding/legacy-mb-korean [ Slow ]
 crbug.com/736056 external/wpt/encoding/legacy-mb-tchinese [ Slow ]
+
+# When we enable snapshot feature, adding an external reference table makes isolate
+# creation slower, and these tests create too many isolates in a test.
+crbug.com/724496 virtual/off-main-thread-fetch/external/wpt/service-workers/service-worker/register-link-element.https.html [ Slow ]
+crbug.com/724496 external/wpt/service-workers/service-worker/register-link-element.https.html [ Slow ]
+crbug.com/724496 external/wpt/service-workers/service-worker/registration.https.html [ Slow ]