The function source returned by v8::internal::JSFunction::ToString for builtins installed by blink have been "function () {}" until now, since they use the internal empty function. The script is marked as native, but not as hidden, so we don't end up with "function () { [native code] }". Now that we are refactoring this [0] and removing the "hidden" flag, this will change.
Affected tests are:
fast/workers/constructor-proto.html
http/tests/w3c/webperf/approved/navigation-timing/html/idlharness.html
imported/wpt/WebIDL/ecmascript-binding/es-exceptions/constructor-object.html
imported/wpt/dom/interfaces.html
inspector/sources/debugger-ui/watch-expressions-preserve-expansion.html
virtual/sharedarraybuffer/fast/workers/constructor-proto.html
[0] https://codereview.chromium.org/2505853003/
Comment 1 by bugdroid1@chromium.org
, Nov 17 2016