https://bugs.webkit.org/show_bug.cgi?id=39896

Reviewed by Adam Barth.

Passing an empty handle to v8 results in a crash with a stack
trace that doesn't give us much information about the cause of the
crash. Instead, if we check the handles we pass to v8 and crash
when they are empty, we do not make things worse, and should get a
more informative stack trace.

* bindings/scripts/CodeGeneratorV8.pm:
* bindings/scripts/test/V8/V8TestCallback.cpp:
(WebCore::V8TestCallback::callbackWithClass1Param):
(WebCore::V8TestCallback::callbackWithClass2Param):
* bindings/v8/custom/V8CustomSQLStatementErrorCallback.cpp:
(WebCore::V8SQLStatementErrorCallback::handleEvent):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@60754 268f45cc-cd09-0410-ab3c-d52691b4dbfc