Auto merge of #10831 - mskrzypkows:storageevent, r=Ms2ger

"storageevent" argument for Document::createEvent

Fixes  #10736

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="35" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/10831)
<!-- Reviewable:end -->

components/script/dom/document.rs

@@ -70,6 +70,7 @@ use dom::nodelist::NodeList;
 use dom::processinginstruction::ProcessingInstruction;
 use dom::range::Range;
 use dom::servohtmlparser::{ParserRoot, ParserRef, MutNullableParserField};
+use dom::storageevent::StorageEvent;
 use dom::stylesheetlist::StyleSheetList;
 use dom::text::Text;
 use dom::touch::Touch;
@@ -2171,6 +2172,8 @@ impl DocumentMethods for Document {
                 )),
             "webglcontextevent" =>
                 Ok(Root::upcast(WebGLContextEvent::new_uninitialized(GlobalRef::Window(&self.window)))),
+            "storageevent" =>
+                Ok(Root::upcast(StorageEvent::new_uninitialized(&self.window, self.URL()))),
             _ =>
                 Err(Error::NotSupported),
         }

components/script/dom/storageevent.rs

@@ -12,6 +12,7 @@ use dom::bindings::js::{JS, MutNullableHeap, Root, RootedReference};
 use dom::bindings::reflector::reflect_dom_object;
 use dom::event::{Event, EventBubbles, EventCancelable};
 use dom::storage::Storage;
+use dom::window::Window;
 use string_cache::Atom;
 use util::str::DOMString;
 
@@ -42,6 +43,13 @@ impl StorageEvent {
         }
     }
 
+    pub fn new_uninitialized(window: &Window,
+                             url: DOMString) -> Root<StorageEvent> {
+        reflect_dom_object(box StorageEvent::new_inherited(None, None, None, url, None),
+                           GlobalRef::Window(window),
+                           StorageEventBinding::Wrap)
+    }
+
     pub fn new(global: GlobalRef,
                type_: Atom,
                bubbles: EventBubbles,