Bug 1476145 part 1. Add a getter to get the nsIDOMWindowUtils from a window. r=nika

The new attribute is not [Cached] because we would need to bump
JSCLASS_GLOBAL_APPLICATION_SLOTS for that and it's not obvious that we should do
that.

dom/base/nsGlobalWindowInner.cpp

@@ -2400,6 +2400,12 @@ nsGlobalWindowInner::GetInstallTrigger()
   return do_AddRef(mInstallTrigger);
 }
 
+nsIDOMWindowUtils*
+nsGlobalWindowInner::GetWindowUtils(ErrorResult& aRv)
+{
+  FORWARD_TO_OUTER_OR_THROW(WindowUtils, (), aRv, nullptr);
+}
+
 nsGlobalWindowInner::CallState
 nsGlobalWindowInner::ShouldReportForServiceWorkerScopeInternal(const nsACString& aScope,
                                                                bool* aResultOut)

dom/base/nsGlobalWindowInner.h

@@ -64,6 +64,7 @@ class nsIBaseWindow;
 class nsIContent;
 class nsICSSDeclaration;
 class nsIDocShellTreeOwner;
+class nsIDOMWindowUtils;
 class nsDOMOfflineResourceList;
 class nsIScrollableFrame;
 class nsIControllers;
@@ -987,6 +988,8 @@ public:
 
   already_AddRefed<mozilla::dom::InstallTriggerImpl> GetInstallTrigger();
 
+  nsIDOMWindowUtils* GetWindowUtils(mozilla::ErrorResult& aRv);
+
   void UpdateTopInnerWindow();
 
   virtual bool IsInSyncOperation() override

dom/base/nsGlobalWindowOuter.cpp

@@ -6818,15 +6818,8 @@ nsGlobalWindowOuter::GetInterfaceInternal(const nsIID& aIID, void** aSink)
   }
 #endif
   else if (aIID.Equals(NS_GET_IID(nsIDOMWindowUtils))) {
-    nsGlobalWindowOuter* outer = GetOuterWindowInternal();
-    NS_ENSURE_TRUE(outer, NS_ERROR_NOT_INITIALIZED);
-
-    if (!mWindowUtils) {
-      mWindowUtils = new nsDOMWindowUtils(outer);
-    }
-
-    *aSink = mWindowUtils;
-    NS_ADDREF(((nsISupports *) *aSink));
+    nsCOMPtr<nsIDOMWindowUtils> utils = WindowUtils();
+    utils.forget(aSink);
   }
   else if (aIID.Equals(NS_GET_IID(nsILoadContext))) {
     nsGlobalWindowOuter* outer = GetOuterWindowInternal();
@@ -7391,6 +7384,15 @@ nsGlobalWindowOuter::GetWindowRootOuter()
   return root.forget().downcast<nsWindowRoot>();
 }
 
+nsIDOMWindowUtils*
+nsGlobalWindowOuter::WindowUtils()
+{
+  if (!mWindowUtils) {
+    mWindowUtils = new nsDOMWindowUtils(this);
+  }
+  return mWindowUtils;
+}
+
 //Note: This call will lock the cursor, it will not change as it moves.
 //To unlock, the cursor must be set back to CURSOR_AUTO.
 void

dom/base/nsGlobalWindowOuter.h

@@ -61,6 +61,7 @@ class nsIBaseWindow;
 class nsIContent;
 class nsICSSDeclaration;
 class nsIDocShellTreeOwner;
+class nsIDOMWindowUtils;
 class nsIScrollableFrame;
 class nsIControllers;
 class nsIJSID;
@@ -740,6 +741,8 @@ public:
 
   already_AddRefed<nsWindowRoot> GetWindowRootOuter();
 
+  nsIDOMWindowUtils* WindowUtils();
+
   virtual bool IsInSyncOperation() override
   {
     return GetExtantDoc() && GetExtantDoc()->IsInSyncOperation();

dom/bindings/Bindings.conf

@@ -1833,6 +1833,7 @@ addExternalIface('MozTreeView', nativeType='nsITreeView',
 addExternalIface('MozWakeLockListener', headerFile='nsIDOMWakeLockListener.h')
 addExternalIface('nsIBrowserDOMWindow', nativeType='nsIBrowserDOMWindow',
                  notflattened=True)
+addExternalIface('nsIDOMWindowUtils', nativeType='nsIDOMWindowUtils', notflattened=True)
 addExternalIface('nsIEventTarget', nativeType='nsIEventTarget', notflattened=True)
 addExternalIface('nsIFile', nativeType='nsIFile', notflattened=True)
 addExternalIface('nsILoadGroup', nativeType='nsILoadGroup',

dom/webidl/Window.webidl

@@ -21,6 +21,7 @@
 interface IID;
 interface nsIBrowserDOMWindow;
 interface XULControllers;
+interface nsIDOMWindowUtils;
 
 typedef OfflineResourceList ApplicationCache;
 
@@ -357,6 +358,12 @@ partial interface Window {
    */
   [Replaceable]
   readonly attribute InstallTriggerImpl? InstallTrigger;
+
+  /**
+   * Get the nsIDOMWindowUtils for this window.
+   */
+  [Constant, Throws, ChromeOnly]
+  readonly attribute nsIDOMWindowUtils windowUtils;
 };
 
 Window implements TouchEventHandlers;