diff -r 000000000000 -r 6474c204b198 ipc/ipdl/test/cxx/TestHangs.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ipc/ipdl/test/cxx/TestHangs.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,87 @@
+#ifndef mozilla__ipdltest_TestHangs_h
+#define mozilla__ipdltest_TestHangs_h 1
+
+#include "mozilla/_ipdltest/IPDLUnitTests.h"
+
+#include "mozilla/_ipdltest/PTestHangsParent.h"
+#include "mozilla/_ipdltest/PTestHangsChild.h"
+
+namespace mozilla {
+namespace _ipdltest {
+
+
+class TestHangsParent :
+    public PTestHangsParent
+{
+public:
+    TestHangsParent();
+    virtual ~TestHangsParent();
+
+    static bool RunTestInProcesses() { return true; }
+
+    // FIXME/bug 703320 Disabled because parent kills child proc, not
+    //                  clear how that should work in threads.
+    static bool RunTestInThreads() { return false; }
+
+    void Main();
+
+protected:
+    virtual bool ShouldContinueFromReplyTimeout() MOZ_OVERRIDE;
+
+    virtual bool RecvNonce() {
+        return true;
+    }
+
+    virtual bool AnswerStackFrame() MOZ_OVERRIDE;
+
+    virtual void ActorDestroy(ActorDestroyReason why) MOZ_OVERRIDE
+    {
+        if (AbnormalShutdown != why)
+            fail("unexpected destruction!");  
+        passed("ok");
+        QuitParent();
+    }
+
+    void CleanUp();
+
+    bool mDetectedHang;
+};
+
+
+class TestHangsChild :
+    public PTestHangsChild
+{
+public:
+    TestHangsChild();
+    virtual ~TestHangsChild();
+
+protected:
+    virtual bool RecvStart() MOZ_OVERRIDE {
+        if (!SendNonce())
+            fail("sending Nonce");
+        return true;
+    }
+
+    virtual bool AnswerStackFrame() MOZ_OVERRIDE
+    {
+        if (CallStackFrame())
+            fail("should have failed");
+        return true;
+    }
+
+    virtual bool AnswerHang() MOZ_OVERRIDE;
+
+    virtual void ActorDestroy(ActorDestroyReason why) MOZ_OVERRIDE
+    {
+        if (AbnormalShutdown != why)
+            fail("unexpected destruction!");
+        QuitChild();
+    }
+};
+
+
+} // namespace _ipdltest
+} // namespace mozilla
+
+
+#endif // ifndef mozilla__ipdltest_TestHangs_h