bug 1271436 - use do_GetInterface() a little less r=smaug

dom/base/nsFrameLoader.cpp

@@ -2103,10 +2103,9 @@ nsFrameLoader::MaybeCreateDocShell()
 
   if (OwnerIsMozBrowserOrAppFrame()) {
     // For inproc frames, set the docshell properties.
-    nsCOMPtr<nsIDocShellTreeItem> item = do_GetInterface(docShell);
     nsAutoString name;
     if (mOwnerContent->GetAttr(kNameSpaceID_None, nsGkAtoms::name, name)) {
-      item->SetName(name);
+      docShell->SetName(name);
     }
     mDocShell->SetFullscreenAllowed(
       mOwnerContent->HasAttr(kNameSpaceID_None, nsGkAtoms::allowfullscreen) ||

dom/speakermanager/SpeakerManager.cpp

@@ -105,7 +105,7 @@ SpeakerManager::Init(nsPIDOMWindowInner* aWindow)
 {
   BindToOwner(aWindow);
 
-  nsCOMPtr<nsIDocShell> docshell = do_GetInterface(GetOwner());
+  nsCOMPtr<nsIDocShell> docshell = GetOwner()->GetDocShell();
   NS_ENSURE_TRUE_VOID(docshell);
   docshell->GetIsActive(&mVisible);
 

dom/workers/ScriptLoader.cpp

@@ -910,7 +910,7 @@ private:
     if (topWorkerPrivate->IsDedicatedWorker()) {
       nsCOMPtr<nsPIDOMWindowInner> window = topWorkerPrivate->GetWindow();
       if (window) {
-        nsCOMPtr<nsIDocShell> docShell = do_GetInterface(window);
+        nsCOMPtr<nsIDocShell> docShell = window->GetDocShell();
         if (docShell) {
           nsresult rv = docShell->GetDefaultLoadFlags(&loadFlags);
           NS_ENSURE_SUCCESS(rv, rv);