Bug 761695 - Hoist getInnerObject into XrayTraits. r=peterv

The only special handling here with wrapped natives is to make sure that we
bypass outer windows. But we can do this with js::UnwrapObject.

js/xpconnect/wrappers/XrayWrapper.cpp

@@ -333,6 +333,10 @@ public:
 
 class XrayTraits
 {
+public:
+    static JSObject* getInnerObject(JSObject *wrapper) {
+        return js::UnwrapObject(wrapper, /* stopAtOuter = */ false);
+    }
 };
 
 class XPCWrappedNativeXrayTraits : public XrayTraits
@@ -352,7 +356,6 @@ public:
     {
         return getHolderObject(wrapper);
     }
-    static JSObject* getInnerObject(JSObject *wrapper);
 
     static bool isResolving(JSContext *cx, JSObject *holder, jsid id);
 
@@ -387,10 +390,6 @@ public:
     {
         return getHolderObject(cx, wrapper, true);
     }
-    static JSObject* getInnerObject(JSObject *wrapper)
-    {
-        return &js::GetProxyPrivate(wrapper).toObject();
-    }
 
     static bool isResolving(JSContext *cx, JSObject *holder, jsid id)
     {
@@ -433,10 +432,6 @@ public:
     {
         return getHolderObject(cx, wrapper, true);
     }
-    static JSObject* getInnerObject(JSObject *wrapper)
-    {
-        return &js::GetProxyPrivate(wrapper).toObject();
-    }
 
     static bool isResolving(JSContext *cx, JSObject *holder, jsid id)
     {
@@ -484,7 +479,7 @@ GetWrappedNativeFromHolder(JSObject *holder)
 {
     MOZ_ASSERT(js::GetObjectJSClass(holder) == &HolderClass);
     JSObject *wrapper = &js::GetReservedSlot(holder, JSSLOT_WRAPPER).toObject();
-    return GetWrappedNative(js::UnwrapObject(wrapper, /* stopAtOuter = */ false));
+    return GetWrappedNative(XrayTraits::getInnerObject(wrapper));
 }
 
 static JSObject *
@@ -512,12 +507,6 @@ FindWrapper(JSContext *cx, JSObject *wrapper)
     return wrapper;
 }
 
-JSObject*
-XPCWrappedNativeXrayTraits::getInnerObject(JSObject *wrapper)
-{
-    return GetWrappedNativeObjectFromHolder(getHolderObject(wrapper));
-}
-
 bool
 XPCWrappedNativeXrayTraits::isResolving(JSContext *cx, JSObject *holder,
                                         jsid id)