Bug 1512029 part 2 - Some CompartmentPrivate changes for same-compartment realms. r=bzbarsky

Differential Revision: https://phabricator.services.mozilla.com/D14253

--HG--
extra : moz-landing-system : lando

js/xpconnect/src/XPCJSRuntime.cpp

@@ -195,6 +195,7 @@ CompartmentPrivate::CompartmentPrivate(JS::Compartment* c,
       hasExclusiveExpandos(false),
       universalXPConnectEnabled(false),
       forcePermissiveCOWs(false),
+      wasShutdown(false),
       mWrappedJSMap(JSObject2WrappedJSMap::newMap(XPC_JS_MAP_LENGTH)) {
   MOZ_COUNT_CTOR(xpc::CompartmentPrivate);
   mozilla::PodArrayZero(wrapperDenialWarnings);
@@ -206,7 +207,12 @@ CompartmentPrivate::~CompartmentPrivate() {
 }
 
 void CompartmentPrivate::SystemIsBeingShutDown() {
-  mWrappedJSMap->ShutdownMarker();
+  // We may call this multiple times when the compartment contains more than one
+  // realm.
+  if (!wasShutdown) {
+    mWrappedJSMap->ShutdownMarker();
+    wasShutdown = true;
+  }
 }
 
 RealmPrivate::RealmPrivate(JS::Realm* realm)

js/xpconnect/src/XPCWrappedNativeScope.cpp

@@ -86,12 +86,14 @@ XPCWrappedNativeScope::XPCWrappedNativeScope(
 
   nsIPrincipal* principal = GetPrincipal();
 
-  // Create the compartment private.
+  // Create the compartment private if needed.
   JS::Compartment* c = js::GetObjectCompartment(aGlobal);
-  MOZ_ASSERT(!JS_GetCompartmentPrivate(c));
-  CompartmentPrivate* priv =
-      new CompartmentPrivate(c, BasePrincipal::Cast(principal), aSite);
-  JS_SetCompartmentPrivate(c, priv);
+  if (CompartmentPrivate* priv = CompartmentPrivate::Get(c)) {
+    MOZ_ASSERT(priv->originInfo.IsSameOrigin(principal));
+  } else {
+    priv = new CompartmentPrivate(c, BasePrincipal::Cast(principal), aSite);
+    JS_SetCompartmentPrivate(c, priv);
+  }
 
   // Attach ourselves to the realm private.
   Realm* realm = JS::GetObjectRealmOrNull(aGlobal);

js/xpconnect/src/xpcprivate.h

@@ -2807,6 +2807,9 @@ class CompartmentPrivate {
   // Using it in production is inherently unsafe.
   bool forcePermissiveCOWs;
 
+  // Whether SystemIsBeingShutDown has been called on this compartment.
+  bool wasShutdown;
+
   // Whether we've emitted a warning about a property that was filtered out
   // by a security wrapper. See XrayWrapper.cpp.
   bool wrapperDenialWarnings[WrapperDenialTypeCount];