Bug 1361975 window.location is not nullable, r=bz

This patch adds a check on mDocShell in order to do not throw exceptions when
Location is used with a null mDocShell. This is needed because the location
object is not nullable anymore and it can be used also when the window is not
connected to a docshell.

dom/base/Location.cpp

@@ -87,19 +87,6 @@ NS_IMPL_CYCLE_COLLECTION_TRACE_WRAPPERCACHE(Location)
 NS_IMPL_CYCLE_COLLECTING_ADDREF(Location)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(Location)
 
-void
-Location::SetDocShell(nsIDocShell *aDocShell)
-{
-   mDocShell = do_GetWeakReference(aDocShell);
-}
-
-nsIDocShell *
-Location::GetDocShell()
-{
-  nsCOMPtr<nsIDocShell> docshell(do_QueryReferent(mDocShell));
-  return docshell;
-}
-
 nsresult
 Location::CheckURL(nsIURI* aURI, nsIDocShellLoadInfo** aLoadInfo)
 {
@@ -210,8 +197,12 @@ Location::GetURI(nsIURI** aURI, bool aGetInnermostURI)
 {
   *aURI = nullptr;
 
-  nsresult rv;
   nsCOMPtr<nsIDocShell> docShell(do_QueryReferent(mDocShell));
+  if (!mDocShell) {
+    return NS_OK;
+  }
+
+  nsresult rv;
   nsCOMPtr<nsIWebNavigation> webNav(do_QueryInterface(docShell, &rv));
   if (NS_FAILED(rv)) {
     return rv;
@@ -896,9 +887,10 @@ Location::GetSourceBaseURL(JSContext* cx, nsIURI** sourceURL)
   // this happens, try falling back on the current document associated with the
   // docshell. If that fails, just return null and hope that the caller passed
   // an absolute URI.
-  if (!doc && GetDocShell()) {
+  nsCOMPtr<nsIDocShell> docShell(do_QueryReferent(mDocShell));
+  if (!doc && docShell) {
     nsCOMPtr<nsPIDOMWindowOuter> docShellWin =
-      do_QueryInterface(GetDocShell()->GetScriptGlobalObject());
+      do_QueryInterface(docShell->GetScriptGlobalObject());
     if (docShellWin) {
       doc = docShellWin->GetDoc();
     }

dom/base/Location.h

@@ -37,9 +37,6 @@ public:
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_AMBIGUOUS(Location,
                                                          nsIDOMLocation)
 
-  void SetDocShell(nsIDocShell *aDocShell);
-  nsIDocShell *GetDocShell();
-
   // nsIDOMLocation
   NS_DECL_NSIDOMLOCATION
 
@@ -233,7 +230,11 @@ protected:
   // In the case of jar: uris, we sometimes want the place the jar was
   // fetched from as the URI instead of the jar: uri itself.  Pass in
   // true for aGetInnermostURI when that's the case.
+  // Note, this method can return NS_OK with a null value for aURL. This happens
+  // if the docShell is null.
   nsresult GetURI(nsIURI** aURL, bool aGetInnermostURI = false);
+  // Note, this method can return NS_OK with a null value for aURL. This happens
+  // if the docShell is null.
   nsresult GetWritableURI(nsIURI** aURL,
                           // If not null, give it the new ref
                           const nsACString* aNewRef = nullptr);

dom/base/nsGlobalWindow.cpp

@@ -1933,7 +1933,6 @@ nsGlobalWindow::CleanUp()
   mPersonalbar = nullptr;
   mStatusbar = nullptr;
   mScrollbars = nullptr;
-  mLocation = nullptr;
   mHistory = nullptr;
   mCustomElements = nullptr;
   mFrames = nullptr;
@@ -2096,7 +2095,6 @@ nsGlobalWindow::FreeInnerObjects()
     mListenerManager = nullptr;
   }
 
-  mLocation = nullptr;
   mHistory = nullptr;
   mCustomElements = nullptr;
 
@@ -10444,10 +10442,10 @@ nsGlobalWindow::GetLocation(ErrorResult& aError)
 {
   MOZ_RELEASE_ASSERT(IsInnerWindow());
 
-  nsIDocShell *docShell = GetDocShell();
-  if (!mLocation && docShell) {
-    mLocation = new Location(AsInner(), docShell);
+  if (!mLocation) {
+    mLocation = new Location(AsInner(), GetDocShell());
   }
+
   return mLocation;
 }
 

dom/webidl/Window.webidl

@@ -36,7 +36,7 @@ interface nsIDOMCrypto;
   [Unforgeable, StoreInSlot, Pure] readonly attribute Document? document;
   [Throws] attribute DOMString name;
   [PutForwards=href, Unforgeable, Throws,
-   CrossOriginReadable, CrossOriginWritable] readonly attribute Location? location;
+   CrossOriginReadable, CrossOriginWritable] readonly attribute Location location;
   [Throws] readonly attribute History history;
   [Func="CustomElementRegistry::IsCustomElementEnabled"]
   readonly attribute CustomElementRegistry customElements;