diff -r 000000000000 -r 6474c204b198 js/xpconnect/src/XPCContext.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/xpconnect/src/XPCContext.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,69 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim: set ts=8 sts=4 et sw=4 tw=99: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* Per JSContext object. */
+
+#include "xpcprivate.h"
+
+#include "jsapi.h"
+
+/***************************************************************************/
+
+XPCContext::XPCContext(XPCJSRuntime* aRuntime,
+                       JSContext* aJSContext)
+    :   mRuntime(aRuntime),
+        mJSContext(aJSContext),
+        mLastResult(NS_OK),
+        mPendingResult(NS_OK),
+        mCallingLangType(LANG_UNKNOWN)
+{
+    MOZ_COUNT_CTOR(XPCContext);
+
+    PR_INIT_CLIST(&mScopes);
+
+    MOZ_ASSERT(!JS_GetSecondContextPrivate(mJSContext), "Must be null");
+    JS_SetSecondContextPrivate(mJSContext, this);
+}
+
+XPCContext::~XPCContext()
+{
+    MOZ_COUNT_DTOR(XPCContext);
+    MOZ_ASSERT(JS_GetSecondContextPrivate(mJSContext) == this, "Must match this");
+    JS_SetSecondContextPrivate(mJSContext, nullptr);
+
+    // Iterate over our scopes and tell them that we have been destroyed
+    for (PRCList *scopeptr = PR_NEXT_LINK(&mScopes);
+         scopeptr != &mScopes;
+         scopeptr = PR_NEXT_LINK(scopeptr)) {
+        XPCWrappedNativeScope *scope =
+            static_cast<XPCWrappedNativeScope*>(scopeptr);
+        scope->ClearContext();
+    }
+}
+
+void
+XPCContext::DebugDump(int16_t depth)
+{
+#ifdef DEBUG
+    depth--;
+    XPC_LOG_ALWAYS(("XPCContext @ %x", this));
+        XPC_LOG_INDENT();
+        XPC_LOG_ALWAYS(("mRuntime @ %x", mRuntime));
+        XPC_LOG_ALWAYS(("mJSContext @ %x", mJSContext));
+        XPC_LOG_ALWAYS(("mLastResult of %x", mLastResult));
+        XPC_LOG_ALWAYS(("mPendingResult of %x", mPendingResult));
+        XPC_LOG_ALWAYS(("mException @ %x", mException.get()));
+        if (depth && mException) {
+            // XXX show the exception here...
+        }
+
+        XPC_LOG_ALWAYS(("mCallingLangType of %s",
+                        mCallingLangType == LANG_UNKNOWN ? "LANG_UNKNOWN" :
+                        mCallingLangType == LANG_JS      ? "LANG_JS" :
+                        "LANG_NATIVE"));
+        XPC_LOG_OUTDENT();
+#endif
+}