Add tests for trace wrappers

third_party/WebKit/Source/core/testing/DeathAwareScriptWrappable.h

Index: third_party/WebKit/Source/core/testing/DeathAwareScriptWrappable.h
diff --git a/third_party/WebKit/Source/core/testing/DeathAwareScriptWrappable.h b/third_party/WebKit/Source/core/testing/DeathAwareScriptWrappable.h
new file mode 100644
index 0000000000000000000000000000000000000000..cf2ed164eb8b99675ebb5f9181f14881811525ee
--- /dev/null
+++ b/third_party/WebKit/Source/core/testing/DeathAwareScriptWrappable.h
@@ -0,0 +1,46 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef DeathAwareScriptWrappable_h
+#define DeathAwareScriptWrappable_h
+
+#include "bindings/core/v8/ScriptWrappable.h"
+#include "platform/heap/Heap.h"
+#include "wtf/text/WTFString.h"
+#include <signal.h>
+
+namespace blink {
+
+class DeathAwareScriptWrappable : public GarbageCollectedFinalized<DeathAwareScriptWrappable>, public ScriptWrappable {
+    DEFINE_WRAPPERTYPEINFO();
+    static DeathAwareScriptWrappable* s_instance;
+    static bool s_hasDied;
+
+public:
+    virtual ~DeathAwareScriptWrappable()
+    {
+        if (this == s_instance) {
+            s_hasDied = true;
+        }
+    }
+
+    static DeathAwareScriptWrappable* create()
+    {
+        return new DeathAwareScriptWrappable();
+    }
+
+    static bool hasDied() { return s_hasDied; }
+    static void observeDeathsOf(DeathAwareScriptWrappable* instance)
+    {

[haraken, 2016/09/02 10:53:15]

Shall we add DCHECK(!s_instance) (i.e., we're not yet observing anything)?

[Marcel Hlopko, 2016/09/02 12:12:40]

Cannot, it's a static variable, and is reused between tests.

+        s_hasDied = false;
+        s_instance = instance;
+    }
+
+    DEFINE_INLINE_VIRTUAL_TRACE() {}
+    DEFINE_INLINE_VIRTUAL_TRACE_WRAPPERS() {}
+};
+
+} // namespace blink
+
+#endif // DeathAwareScriptWrappable_h