Bug 1289129. When setting up an AutoJSAPI with a global, make sure to expose that global to active JS. r=mccr8

dom/base/ScriptSettings.cpp

@@ -357,6 +357,9 @@ AutoJSAPI::InitInternal(nsIGlobalObject* aGlobalObject, JSObject* aGlobal,
     // too.
     mAutoRequest.emplace(mCx);
   }
+  if (aGlobal) {
+    JS::ExposeObjectToActiveJS(aGlobal);
+  }
   mAutoNullableCompartment.emplace(mCx, aGlobal);
 
   ScriptSettingsStack::Push(this);

dom/base/nsIGlobalObject.h

@@ -56,7 +56,8 @@ public:
   // GetGlobalJSObject may return a gray object.  If this ever changes so that
   // it stops doing that, please simplify the code in FindAssociatedGlobal in
   // BindingUtils.h that does JS::ExposeObjectToActiveJS on the return value of
-  // GetGlobalJSObject.
+  // GetGlobalJSObject.  Also, in that case the JS::ExposeObjectToActiveJS in
+  // AutoJSAPI::InitInternal can probably be removed.
   virtual JSObject* GetGlobalJSObject() = 0;
 
   // This method is not meant to be overridden.