--- a/js/xpconnect/src/XPCCallContext.cpp
+++ b/js/xpconnect/src/XPCCallContext.cpp
@@ -8,111 +8,110 @@
 
 #include "mozilla/Util.h"
 #include "AccessCheck.h"
 
 #include "xpcprivate.h"
 
 using namespace mozilla;
 using namespace xpc;
+using namespace JS;
 
 XPCCallContext::XPCCallContext(XPCContext::LangType callerLanguage,
-                               JSContext* cx    /* = nullptr    */,
-                               JSObject* obj    /* = nullptr    */,
-                               JSObject* funobj /* = nullptr    */,
-                               jsid name        /* = JSID_VOID */,
-                               unsigned argc    /* = NO_ARGS   */,
-                               jsval *argv      /* = nullptr    */,
-                               jsval *rval      /* = nullptr    */)
+                               JSContext* cx       /* = GetDefaultJSContext() */,
+                               HandleObject obj    /* = nullptr               */,
+                               HandleObject funobj /* = nullptr               */,
+                               HandleId name       /* = JSID_VOID             */,
+                               unsigned argc       /* = NO_ARGS               */,
+                               jsval *argv         /* = nullptr               */,
+                               jsval *rval         /* = nullptr               */)
     :   mState(INIT_FAILED),
         mXPC(nsXPConnect::GetXPConnect()),
         mXPCContext(nullptr),
         mJSContext(cx),
         mContextPopRequired(false),
         mDestroyJSContextInDestructor(false),
         mCallerLanguage(callerLanguage),
-        mScopeForNewJSObjects(xpc_GetSafeJSContext()),
-        mFlattenedJSObject(xpc_GetSafeJSContext()),
+        mScopeForNewJSObjects(cx),
+        mFlattenedJSObject(cx),
         mWrapper(nullptr),
         mTearOff(nullptr),
-        mName(xpc_GetSafeJSContext())
+        mName(cx)
 {
+    MOZ_ASSERT(cx);
     Init(callerLanguage, callerLanguage == NATIVE_CALLER, obj, funobj,
          INIT_SHOULD_LOOKUP_WRAPPER, name, argc, argv, rval);
 }
 
 XPCCallContext::XPCCallContext(XPCContext::LangType callerLanguage,
                                JSContext* cx,
                                JSBool callBeginRequest,
-                               JSObject* obj,
-                               JSObject* flattenedJSObject,
+                               HandleObject obj,
+                               HandleObject flattenedJSObject,
                                XPCWrappedNative* wrapper,
                                XPCWrappedNativeTearOff* tearOff)
     :   mState(INIT_FAILED),
         mXPC(nsXPConnect::GetXPConnect()),
         mXPCContext(nullptr),
         mJSContext(cx),
         mContextPopRequired(false),
         mDestroyJSContextInDestructor(false),
         mCallerLanguage(callerLanguage),
-        mScopeForNewJSObjects(xpc_GetSafeJSContext()),
-        mFlattenedJSObject(xpc_GetSafeJSContext(), flattenedJSObject),
+        mScopeForNewJSObjects(cx),
+        mFlattenedJSObject(cx, flattenedJSObject),
         mWrapper(wrapper),
         mTearOff(tearOff),
-        mName(xpc_GetSafeJSContext())
+        mName(cx)
 {
-    Init(callerLanguage, callBeginRequest, obj, nullptr,
-         WRAPPER_PASSED_TO_CONSTRUCTOR, JSID_VOID, NO_ARGS,
+    MOZ_ASSERT(cx);
+    Init(callerLanguage, callBeginRequest, obj, NullPtr(),
+         WRAPPER_PASSED_TO_CONSTRUCTOR, JSID_VOIDHANDLE, NO_ARGS,
          nullptr, nullptr);
 }
 
 #define IS_TEAROFF_CLASS(clazz) ((clazz) == &XPC_WN_Tearoff_JSClass)
 
+
+// static
+JSContext *
+XPCCallContext::GetDefaultJSContext()
+{
+    // This is slightly questionable. If called without an explicit
+    // JSContext (generally a call to a wrappedJS) we will use the JSContext
+    // on the top of the JSContext stack - if there is one - *before*
+    // falling back on the safe JSContext.
+    // This is good AND bad because it makes calls from JS -> native -> JS
+    // have JS stack 'continuity' for purposes of stack traces etc.
+    // Note: this *is* what the pre-XPCCallContext xpconnect did too.
+
+    XPCJSContextStack* stack = XPCJSRuntime::Get()->GetJSContextStack();
+    JSContext *topJSContext = stack->Peek();
+
+    return topJSContext ? topJSContext : stack->GetSafeJSContext();
+}
+
 void
 XPCCallContext::Init(XPCContext::LangType callerLanguage,
                      JSBool callBeginRequest,
-                     JSObject* obj,
-                     JSObject* funobj,
+                     HandleObject obj,
+                     HandleObject funobj,
                      WrapperInitOptions wrapperInitOptions,
-                     jsid name,
+                     HandleId name,
                      unsigned argc,
                      jsval *argv,
                      jsval *rval)
 {
+    NS_ASSERTION(mJSContext, "No JSContext supplied to XPCCallContext");
+
     if (!mXPC)
         return;
 
     XPCJSContextStack* stack = XPCJSRuntime::Get()->GetJSContextStack();
-
-    if (!stack) {
-        // If we don't have a stack we're probably in shutdown.
-        mJSContext = nullptr;
-        return;
-    }
-
     JSContext *topJSContext = stack->Peek();
 
-    if (!mJSContext) {
-        // This is slightly questionable. If called without an explicit
-        // JSContext (generally a call to a wrappedJS) we will use the JSContext
-        // on the top of the JSContext stack - if there is one - *before*
-        // falling back on the safe JSContext.
-        // This is good AND bad because it makes calls from JS -> native -> JS
-        // have JS stack 'continuity' for purposes of stack traces etc.
-        // Note: this *is* what the pre-XPCCallContext xpconnect did too.
-
-        if (topJSContext) {
-            mJSContext = topJSContext;
-        } else {
-            mJSContext = stack->GetSafeJSContext();
-            if (!mJSContext)
-                return;
-        }
-    }
-
     if (topJSContext != mJSContext) {
         if (!stack->Push(mJSContext)) {
             NS_ERROR("bad!");
             return;
         }
         mContextPopRequired = true;
     }
 
@@ -199,25 +198,25 @@ XPCCallContext::SetName(jsid name)
 {
     CHECK_STATE(HAVE_OBJECT);
 
     mName = name;
 
     if (mTearOff) {
         mSet = nullptr;
         mInterface = mTearOff->GetInterface();
-        mMember = mInterface->FindMember(name);
+        mMember = mInterface->FindMember(mName);
         mStaticMemberIsLocal = true;
         if (mMember && !mMember->IsConstant())
             mMethodIndex = mMember->GetIndex();
     } else {
         mSet = mWrapper ? mWrapper->GetSet() : nullptr;
 
         if (mSet &&
-            mSet->FindMember(name, &mMember, &mInterface,
+            mSet->FindMember(mName, &mMember, &mInterface,
                              mWrapper->HasProto() ?
                              mWrapper->GetProto()->GetSet() :
                              nullptr,
                              &mStaticMemberIsLocal)) {
             if (mMember && !mMember->IsConstant())
                 mMethodIndex = mMember->GetIndex();
         } else {
             mMember = nullptr;
@@ -454,19 +453,18 @@ XPCLazyCallContext::AssertContextIsTopOf
     XPCJSContextStack* stack = XPCJSRuntime::Get()->GetJSContextStack();
 
     JSContext *topJSContext = stack->Peek();
     NS_ASSERTION(cx == topJSContext, "wrong context on XPCJSContextStack!");
 }
 #endif
 
 XPCWrappedNative*
-XPCCallContext::UnwrapThisIfAllowed(JSObject *object, JSObject *fun, unsigned argc)
+XPCCallContext::UnwrapThisIfAllowed(HandleObject obj, HandleObject fun, unsigned argc)
 {
-    JS::Rooted<JSObject *> obj(mJSContext, object);
     // We should only get here for objects that aren't safe to unwrap.
     MOZ_ASSERT(!js::CheckedUnwrap(obj));
     MOZ_ASSERT(js::IsObjectInContextCompartment(obj, mJSContext));
 
     // We can't do anything here without a function.
     if (!fun)
         return nullptr;
 
@@ -477,17 +475,17 @@ XPCCallContext::UnwrapThisIfAllowed(JSOb
     // unfortunately our access checks are based on the object class name and
     // property name. So we cheat a little bit here - we verify that the object
     // does indeed implement the method's Interface, and then just check that we
     // can successfully access property with method's name from the object.
 
     // First, get the XPCWN out of the underlying object. We should have a wrapper
     // here, potentially an outer window proxy, and then an XPCWN.
     MOZ_ASSERT(js::IsWrapper(obj));
-    JSObject *unwrapped = js::UncheckedUnwrap(obj, /* stopAtOuter = */ false);
+    RootedObject unwrapped(mJSContext, js::UncheckedUnwrap(obj, /* stopAtOuter = */ false));
     MOZ_ASSERT(unwrapped == JS_ObjectToInnerObject(mJSContext, js::Wrapper::wrappedObject(obj)));
 
     // Make sure we have an XPCWN, and grab it.
     MOZ_ASSERT(!IS_SLIM_WRAPPER(unwrapped), "security wrapping morphs slim wrappers");
     if (!IS_WRAPPER_CLASS(js::GetObjectClass(unwrapped)))
         return nullptr;
     XPCWrappedNative *wn = (XPCWrappedNative*)js::GetObjectPrivate(unwrapped);
 

--- a/js/xpconnect/src/XPCJSID.cpp
+++ b/js/xpconnect/src/XPCJSID.cpp
@@ -832,19 +832,18 @@ nsJSCID::Construct(nsIXPConnectWrappedNa
                    bool *_retval)
 {
     RootedObject obj(cx, objArg);
     XPCJSRuntime* rt = nsXPConnect::GetRuntimeInstance();
     if (!rt)
         return NS_ERROR_FAILURE;
 
     // 'push' a call context and call on it
-    XPCCallContext ccx(JS_CALLER, cx, obj, nullptr,
-                       rt->GetStringID(XPCJSRuntime::IDX_CREATE_INSTANCE),
-                       argc, argv, vp);
+    RootedId name(cx, rt->GetStringID(XPCJSRuntime::IDX_CREATE_INSTANCE));
+    XPCCallContext ccx(JS_CALLER, cx, obj, NullPtr(), name, argc, argv, vp);
 
     *_retval = XPCWrappedNative::CallMethod(ccx);
     return NS_OK;
 }
 
 /* bool hasInstance (in nsIXPConnectWrappedNative wrapper, in JSContextPtr cx, in JSObjectPtr obj, in jsval val, out bool bp); */
 NS_IMETHODIMP
 nsJSCID::HasInstance(nsIXPConnectWrappedNative *wrapper,

--- a/js/xpconnect/src/XPCWrappedJSClass.cpp
+++ b/js/xpconnect/src/XPCWrappedJSClass.cpp
@@ -620,16 +620,18 @@ nsXPCWrappedJSClass::DelegatedQueryInter
 
     // We can't have a cached wrapper.
     if (aIID.Equals(NS_GET_IID(nsWrapperCache))) {
         *aInstancePtr = nullptr;
         return NS_NOINTERFACE;
     }
 
     JSContext *context = GetContextFromObject(self->GetJSObject());
+    if (!context)
+        context = XPCCallContext::GetDefaultJSContext();
     XPCCallContext ccx(NATIVE_CALLER, context);
     if (!ccx.IsValid()) {
         *aInstancePtr = nullptr;
         return NS_NOINTERFACE;
     }
 
     // We support nsISupportsWeakReference iff the root wrapped JSObject
     // claims to support it in its QueryInterface implementation.
@@ -1137,16 +1139,18 @@ nsXPCWrappedJSClass::CallMethod(nsXPCWra
     const char* name = info->name;
     JSBool foundDependentParam;
 
     // Make sure not to set the callee on ccx until after we've gone through
     // the whole nsIXPCFunctionThisTranslator bit.  That code uses ccx to
     // convert natives to JSObjects, but we do NOT plan to pass those JSObjects
     // to our real callee.
     JSContext *context = GetContextFromObject(wrapper->GetJSObject());
+    if (!context)
+        context = XPCCallContext::GetDefaultJSContext();
     XPCCallContext ccx(NATIVE_CALLER, context);
     if (!ccx.IsValid())
         return retval;
 
     XPCContext *xpcc = ccx.GetXPCContext();
     JSContext *cx = xpc_UnmarkGrayContext(ccx.GetJSContext());
 
     if (!cx || !xpcc || !IsReflectable(methodIndex))

--- a/js/xpconnect/src/XPCWrappedNativeJSOps.cpp
+++ b/js/xpconnect/src/XPCWrappedNativeJSOps.cpp
@@ -72,33 +72,33 @@ ToStringGuts(XPCCallContext& ccx)
     return true;
 }
 
 /***************************************************************************/
 
 static JSBool
 XPC_WN_Shared_ToString(JSContext *cx, unsigned argc, jsval *vp)
 {
-    JSObject *obj = JS_THIS_OBJECT(cx, vp);
+    RootedObject obj(cx, JS_THIS_OBJECT(cx, vp));
     if (!obj)
         return false;
 
     if (IS_SLIM_WRAPPER(obj)) {
         XPCNativeScriptableInfo *si =
             GetSlimWrapperProto(obj)->GetScriptableInfo();
 #ifdef DEBUG
 #  define FMT_ADDR " @ 0x%p"
 #  define FMT_STR(str) str
 #  define PARAM_ADDR(w) , w
 #else
 #  define FMT_ADDR ""
 #  define FMT_STR(str)
 #  define PARAM_ADDR(w)
 #endif
-        char *sz = JS_smprintf("[object %s" FMT_ADDR FMT_STR(" (native") FMT_ADDR FMT_STR(")") "]", si->GetJSClass()->name PARAM_ADDR(obj) PARAM_ADDR(xpc_GetJSPrivate(obj)));
+        char *sz = JS_smprintf("[object %s" FMT_ADDR FMT_STR(" (native") FMT_ADDR FMT_STR(")") "]", si->GetJSClass()->name PARAM_ADDR(obj.get()) PARAM_ADDR(xpc_GetJSPrivate(obj)));
         if (!sz)
             return false;
 
         JSString* str = JS_NewStringCopyZ(cx, sz);
         JS_smprintf_free(sz);
         if (!str)
             return false;
 
@@ -468,17 +468,17 @@ DefinePropertyIfFound(XPCCallContext& cc
 }
 
 /***************************************************************************/
 /***************************************************************************/
 
 static JSBool
 XPC_WN_OnlyIWrite_AddPropertyStub(JSContext *cx, JSHandleObject obj, JSHandleId id, JSMutableHandleValue vp)
 {
-    XPCCallContext ccx(JS_CALLER, cx, obj, nullptr, id);
+    XPCCallContext ccx(JS_CALLER, cx, obj, NullPtr(), id);
     XPCWrappedNative* wrapper = ccx.GetWrapper();
     THROW_AND_RETURN_IF_BAD_WRAPPER(cx, wrapper);
 
     // Allow only XPConnect to add/set the property
     if (ccx.GetResolveName() == id)
         return true;
 
     return Throw(NS_ERROR_XPC_CANT_MODIFY_PROP_ON_WN, cx);
@@ -696,17 +696,17 @@ XPC_WN_NoHelper_Trace(JSTracer *trc, JSO
 {
     MarkWrappedNative(trc, obj);
 }
 
 static JSBool
 XPC_WN_NoHelper_Resolve(JSContext *cx, JSHandleObject obj, JSHandleId id)
 {
     MORPH_SLIM_WRAPPER(cx, obj);
-    XPCCallContext ccx(JS_CALLER, cx, obj, nullptr, id);
+    XPCCallContext ccx(JS_CALLER, cx, obj, NullPtr(), id);
     XPCWrappedNative* wrapper = ccx.GetWrapper();
     THROW_AND_RETURN_IF_BAD_WRAPPER(cx, wrapper);
 
     XPCNativeSet* set = ccx.GetSet();
     if (!set)
         return true;
 
     // Don't resolve properties that are on our prototype.
@@ -957,17 +957,17 @@ XPC_WN_Helper_CheckAccess(JSContext *cx,
 }
 
 static JSBool
 XPC_WN_Helper_Call(JSContext *cx, unsigned argc, jsval *vp)
 {
     // N.B. we want obj to be the callee, not JS_THIS(cx, vp)
     RootedObject obj(cx, JSVAL_TO_OBJECT(JS_CALLEE(cx, vp)));
 
-    XPCCallContext ccx(JS_CALLER, cx, obj, nullptr, JSID_VOID,
+    XPCCallContext ccx(JS_CALLER, cx, obj, NullPtr(), JSID_VOIDHANDLE,
                        argc, JS_ARGV(cx, vp), vp);
     if (!ccx.IsValid())
         return false;
 
     MOZ_ASSERT(obj == ccx.GetFlattenedJSObject());
 
     SLIM_LOG_WILL_MORPH(cx, obj);
     PRE_HELPER_STUB_NO_SLIM
@@ -977,17 +977,17 @@ XPC_WN_Helper_Call(JSContext *cx, unsign
 
 static JSBool
 XPC_WN_Helper_Construct(JSContext *cx, unsigned argc, jsval *vp)
 {
     RootedObject obj(cx, JSVAL_TO_OBJECT(JS_CALLEE(cx, vp)));
     if (!obj)
         return false;
 
-    XPCCallContext ccx(JS_CALLER, cx, obj, nullptr, JSID_VOID,
+    XPCCallContext ccx(JS_CALLER, cx, obj, NullPtr(), JSID_VOIDHANDLE,
                        argc, JS_ARGV(cx, vp), vp);
     if (!ccx.IsValid())
         return false;
 
     MOZ_ASSERT(obj == ccx.GetFlattenedJSObject());
 
     SLIM_LOG_WILL_MORPH(cx, obj);
     PRE_HELPER_STUB_NO_SLIM
@@ -1467,17 +1467,18 @@ XPC_WN_CallMethod(JSContext *cx, unsigne
         const char *funname = !funid ? "" : bytes.encodeLatin1(cx, funid) ? bytes.ptr() : "<error>";
         SLIM_LOG_WILL_MORPH_FOR_PROP(cx, obj, funname);
     }
 #endif
     if (IS_SLIM_WRAPPER(obj) && !MorphSlimWrapper(cx, obj))
         return Throw(NS_ERROR_XPC_BAD_OP_ON_WN_PROTO, cx);
 
     obj = FixUpThisIfBroken(obj, funobj);
-    XPCCallContext ccx(JS_CALLER, cx, obj, funobj, JSID_VOID, argc, JS_ARGV(cx, vp), vp);
+    XPCCallContext ccx(JS_CALLER, cx, obj, funobj, JSID_VOIDHANDLE, argc,
+                       JS_ARGV(cx, vp), vp);
     XPCWrappedNative* wrapper = ccx.GetWrapper();
     THROW_AND_RETURN_IF_BAD_WRAPPER(cx, wrapper);
 
     XPCNativeInterface* iface;
     XPCNativeMember*    member;
 
     if (!XPCNativeMember::GetCallInfo(funobj, &iface, &member))
         return Throw(NS_ERROR_XPC_CANT_GET_METHOD_INFO, cx);
@@ -1506,17 +1507,18 @@ XPC_WN_GetterSetter(JSContext *cx, unsig
         SLIM_LOG_WILL_MORPH_FOR_PROP(cx, obj, funname);
     }
 #endif
     if (IS_SLIM_WRAPPER(obj) && !MorphSlimWrapper(cx, obj))
         return Throw(NS_ERROR_XPC_BAD_OP_ON_WN_PROTO, cx);
 
 
     obj = FixUpThisIfBroken(obj, funobj);
-    XPCCallContext ccx(JS_CALLER, cx, obj, funobj, JSID_VOID, argc, JS_ARGV(cx, vp), vp);
+    XPCCallContext ccx(JS_CALLER, cx, obj, funobj, JSID_VOIDHANDLE, argc,
+                       JS_ARGV(cx, vp), vp);
     XPCWrappedNative* wrapper = ccx.GetWrapper();
     THROW_AND_RETURN_IF_BAD_WRAPPER(cx, wrapper);
 
     XPCNativeInterface* iface;
     XPCNativeMember*    member;
 
     if (!XPCNativeMember::GetCallInfo(funobj, &iface, &member))
         return Throw(NS_ERROR_XPC_CANT_GET_METHOD_INFO, cx);

--- a/js/xpconnect/src/xpcprivate.h
+++ b/js/xpconnect/src/xpcprivate.h
@@ -1134,24 +1134,26 @@ public:
     NS_IMETHOD GetArgvPtr(jsval **aResult);
     NS_IMETHOD GetCalleeInterface(nsIInterfaceInfo **aResult);
     NS_IMETHOD GetCalleeClassInfo(nsIClassInfo **aResult);
     NS_IMETHOD GetPreviousCallContext(nsAXPCNativeCallContext **aResult);
     NS_IMETHOD GetLanguage(uint16_t *aResult);
 
     enum {NO_ARGS = (unsigned) -1};
 
+    static JSContext* GetDefaultJSContext();
+
     XPCCallContext(XPCContext::LangType callerLanguage,
-                   JSContext* cx    = nullptr,
-                   JSObject* obj    = nullptr,
-                   JSObject* funobj = nullptr,
-                   jsid id          = JSID_VOID,
-                   unsigned argc    = NO_ARGS,
-                   jsval *argv      = nullptr,
-                   jsval *rval      = nullptr);
+                   JSContext* cx           = GetDefaultJSContext(),
+                   JS::HandleObject obj    = JS::NullPtr(),
+                   JS::HandleObject funobj = JS::NullPtr(),
+                   JS::HandleId id         = JS::JSID_VOIDHANDLE,
+                   unsigned argc           = NO_ARGS,
+                   jsval *argv             = nullptr,
+                   jsval *rval             = nullptr);
 
     virtual ~XPCCallContext();
 
     inline JSBool                       IsValid() const ;
 
     inline nsXPConnect*                 GetXPConnect() const ;
     inline XPCJSRuntime*                GetRuntime() const ;
     inline XPCContext*                  GetXPCContext() const ;
@@ -1223,37 +1225,37 @@ private:
     // no copy ctor or assignment allowed
     XPCCallContext(const XPCCallContext& r); // not implemented
     XPCCallContext& operator= (const XPCCallContext& r); // not implemented
 
     friend class XPCLazyCallContext;
     XPCCallContext(XPCContext::LangType callerLanguage,
                    JSContext* cx,
                    JSBool callBeginRequest,
-                   JSObject* obj,
-                   JSObject* flattenedJSObject,
+                   JS::HandleObject obj,
+                   JS::HandleObject flattenedJSObject,
                    XPCWrappedNative* wn,
                    XPCWrappedNativeTearOff* tearoff);
 
     enum WrapperInitOptions {
         WRAPPER_PASSED_TO_CONSTRUCTOR,
         INIT_SHOULD_LOOKUP_WRAPPER
     };
 
     void Init(XPCContext::LangType callerLanguage,
               JSBool callBeginRequest,
-              JSObject* obj,
-              JSObject* funobj,
+              JS::HandleObject obj,
+              JS::HandleObject funobj,
               WrapperInitOptions wrapperInitOptions,
-              jsid name,
+              JS::HandleId name,
               unsigned argc,
               jsval *argv,
               jsval *rval);
 
-    XPCWrappedNative* UnwrapThisIfAllowed(JSObject *obj, JSObject *fun,
+    XPCWrappedNative* UnwrapThisIfAllowed(JS::HandleObject obj, JS::HandleObject fun,
                                           unsigned argc);
 
 private:
     // posible values for mState
     enum State {
         INIT_FAILED,
         SYSTEM_SHUTDOWN,
         HAVE_CONTEXT,
@@ -1394,22 +1396,24 @@ public:
             return mCcx->GetFlattenedJSObject();
 
         return xpc_UnmarkGrayObject(mFlattenedJSObject);
     }
     XPCCallContext &GetXPCCallContext()
     {
         if (!mCcx) {
             XPCCallContext *data = mData.addr();
+            xpc_UnmarkGrayObject(mObj);
+            xpc_UnmarkGrayObject(mFlattenedJSObject);
             mCcxToDestroy = mCcx =
                 new (data) XPCCallContext(mCallerLanguage, mCx,
                                           mCallBeginRequest == CALL_BEGINREQUEST,
-                                           xpc_UnmarkGrayObject(mObj),
-                                           xpc_UnmarkGrayObject(mFlattenedJSObject),
-                                           mWrapper,
+                                          mObj,
+                                          mFlattenedJSObject,
+                                          mWrapper,
                                           mTearOff);
             if (!mCcx->IsValid()) {
                 NS_ERROR("This is not supposed to fail!");
             }
         }
 
         return *mCcx;
     }

--- a/js/xpconnect/wrappers/XrayWrapper.cpp
+++ b/js/xpconnect/wrappers/XrayWrapper.cpp
@@ -751,17 +751,18 @@ XPCWrappedNativeXrayTraits::resolveNativ
         desc->setter = NULL;
         desc->shortid = 0;
         return true;
     }
 
     desc->obj = NULL;
 
     // This will do verification and the method lookup for us.
-    XPCCallContext ccx(JS_CALLER, cx, getTargetObject(wrapper), nullptr, id);
+    RootedObject target(cx, getTargetObject(wrapper));
+    XPCCallContext ccx(JS_CALLER, cx, target, NullPtr(), id);
 
     // There are no native numeric properties, so we can shortcut here. We will
     // not find the property. However we want to support non shadowing dom
     // specific collection properties like window.frames, so we still have to
     // check for those.
     if (!JSID_IS_STRING(id)) {
         /* Not found */
         return resolveDOMCollectionProperty(cx, wrapper, holder, id, desc, flags);
@@ -1110,18 +1111,18 @@ XPCWrappedNativeXrayTraits::createHolder
 
 bool
 XPCWrappedNativeXrayTraits::call(JSContext *cx, HandleObject wrapper,
                                  const JS::CallArgs &args)
 {
     // Run the resolve hook of the wrapped native.
     XPCWrappedNative *wn = getWN(wrapper);
     if (NATIVE_HAS_FLAG(wn, WantCall)) {
-        XPCCallContext ccx(JS_CALLER, cx, wrapper, nullptr, JSID_VOID, args.length(), args.array(),
-                           args.rval().address());
+        XPCCallContext ccx(JS_CALLER, cx, wrapper, NullPtr(), JSID_VOIDHANDLE, args.length(),
+                           args.array(), args.rval().address());
         if (!ccx.IsValid())
             return false;
         bool ok = true;
         nsresult rv = wn->GetScriptableInfo()->GetCallback()->Call(
             wn, cx, wrapper, args.length(), args.array(), args.rval().address(), &ok);
         if (NS_FAILED(rv)) {
             if (ok)
                 XPCThrower::Throw(rv, cx);
@@ -1135,18 +1136,18 @@ XPCWrappedNativeXrayTraits::call(JSConte
 
 bool
 XPCWrappedNativeXrayTraits::construct(JSContext *cx, HandleObject wrapper,
                                       const JS::CallArgs &args)
 {
     // Run the resolve hook of the wrapped native.
     XPCWrappedNative *wn = getWN(wrapper);
     if (NATIVE_HAS_FLAG(wn, WantConstruct)) {
-        XPCCallContext ccx(JS_CALLER, cx, wrapper, nullptr, JSID_VOID, args.length(), args.array(),
-                           args.rval().address());
+        XPCCallContext ccx(JS_CALLER, cx, wrapper, NullPtr(), JSID_VOIDHANDLE, args.length(),
+                           args.array(), args.rval().address());
         if (!ccx.IsValid())
             return false;
         bool ok = true;
         nsresult rv = wn->GetScriptableInfo()->GetCallback()->Construct(
             wn, cx, wrapper, args.length(), args.array(), args.rval().address(), &ok);
         if (NS_FAILED(rv)) {
             if (ok)
                 XPCThrower::Throw(rv, cx);