Fix edge case of extension with NULL as source string.

test/cctest/test-api.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4653 matching lines @@
   v8::RegisterExtension(new Extension("simpletest", kSimpleExtensionSource));
   const char* extension_names[] = { "simpletest" };
   v8::ExtensionConfiguration extensions(1, extension_names);
   v8::Handle<Context> context = Context::New(&extensions);
   Context::Scope lock(context);
   v8::Handle<Value> result = Script::Compile(v8_str("Foo()"))->Run();
   CHECK_EQ(result, v8::Integer::New(4));
 }
 
 
+THREADED_TEST(NullExtensions) {
+  v8::HandleScope handle_scope;
+  v8::RegisterExtension(new Extension("nulltest", NULL));
+  const char* extension_names[] = { "nulltest" };
+  v8::ExtensionConfiguration extensions(1, extension_names);
+  v8::Handle<Context> context = Context::New(&extensions);
+  Context::Scope lock(context);
+  v8::Handle<Value> result = Script::Compile(v8_str("1+3"))->Run();
+  CHECK_EQ(result, v8::Integer::New(4));
+}
+
+
 static const char* kEmbeddedExtensionSource =
     "function Ret54321(){return 54321;}~~@@$"
     "$%% THIS IS A SERIES OF NON-NULL-TERMINATED STRINGS.";
 static const int kEmbeddedExtensionSourceValidLen = 34;
 
 
 THREADED_TEST(ExtensionMissingSourceLength) {
   v8::HandleScope handle_scope;
   v8::RegisterExtension(new Extension("srclentest_fail",
                                       kEmbeddedExtensionSource));
@@ skipping 12760 matching lines @@
 
   i::Semaphore* sem_;
   volatile int sem_value_;
 };
 
 
 THREADED_TEST(SemaphoreInterruption) {
   ThreadInterruptTest().RunTest();
 }
 #endif  // WIN32