--- a/editor/composer/nsComposerCommandsUpdater.cpp
+++ b/editor/composer/nsComposerCommandsUpdater.cpp
@@ -380,14 +380,12 @@ nsComposerCommandsUpdater::Notify(nsITim
 #if 0
 #pragma mark -
 #endif
 
 
 nsresult
 NS_NewComposerCommandsUpdater(nsISelectionListener** aInstancePtrResult)
 {
-  nsComposerCommandsUpdater* newThang = new nsComposerCommandsUpdater;
-  NS_ENSURE_TRUE(newThang, NS_ERROR_OUT_OF_MEMORY);
-
-  return newThang->QueryInterface(NS_GET_IID(nsISelectionListener),
-                                  (void **)aInstancePtrResult);
+  nsRefPtr<nsComposerCommandsUpdater> newThang = new nsComposerCommandsUpdater;
+  newThang.forget(aInstancePtrResult);
+  return NS_OK;
 }

--- a/editor/libeditor/nsHTMLURIRefObject.cpp
+++ b/editor/libeditor/nsHTMLURIRefObject.cpp
@@ -249,12 +249,12 @@ nsHTMLURIRefObject::SetNode(nsIDOMNode *
 nsresult NS_NewHTMLURIRefObject(nsIURIRefObject** aResult, nsIDOMNode* aNode)
 {
   nsRefPtr<nsHTMLURIRefObject> refObject = new nsHTMLURIRefObject();
   nsresult rv = refObject->SetNode(aNode);
   if (NS_FAILED(rv)) {
     *aResult = 0;
     return rv;
   }
-  return refObject->QueryInterface(NS_GET_IID(nsIURIRefObject),
-                                   (void**)aResult);
+  refObject.forget(aResult);
+  return NS_OK;
 }
 

--- a/editor/txtsvc/nsTextServicesDocument.cpp
+++ b/editor/txtsvc/nsTextServicesDocument.cpp
@@ -1995,31 +1995,31 @@ nsTextServicesDocument::GetDocumentConte
     nsCOMPtr<nsIDOMHTMLElement> bodyElement;
 
     result = htmlDoc->GetBody(getter_AddRefs(bodyElement));
 
     NS_ENSURE_SUCCESS(result, result);
 
     NS_ENSURE_TRUE(bodyElement, NS_ERROR_FAILURE);
 
-    result = bodyElement->QueryInterface(NS_GET_IID(nsIDOMNode), (void **)aNode);
+    bodyElement.forget(aNode);
   }
   else
   {
     // For non-HTML documents, the content root node will be the document element.
 
     nsCOMPtr<nsIDOMElement> docElement;
 
     result = mDOMDocument->GetDocumentElement(getter_AddRefs(docElement));
 
     NS_ENSURE_SUCCESS(result, result);
 
     NS_ENSURE_TRUE(docElement, NS_ERROR_FAILURE);
 
-    result = docElement->QueryInterface(NS_GET_IID(nsIDOMNode), (void **)aNode);
+    docElement.forget(aNode);
   }
 
   return result;
 }
 
 nsresult
 nsTextServicesDocument::CreateDocumentContentRange(nsRange** aRange)
 {

--- a/embedding/components/commandhandler/nsCommandGroup.cpp
+++ b/embedding/components/commandhandler/nsCommandGroup.cpp
@@ -283,30 +283,30 @@ nsControllerCommandGroup::IsCommandInGro
   }
   return NS_OK;
 }
 
 /* nsISimpleEnumerator getGroupsEnumerator (); */
 NS_IMETHODIMP
 nsControllerCommandGroup::GetGroupsEnumerator(nsISimpleEnumerator **_retval)
 {
-  nsGroupsEnumerator *groupsEnum = new nsGroupsEnumerator(mGroupsHash);
-  if (!groupsEnum) return NS_ERROR_OUT_OF_MEMORY;
+  nsRefPtr<nsGroupsEnumerator> groupsEnum = new nsGroupsEnumerator(mGroupsHash);
 
-  return groupsEnum->QueryInterface(NS_GET_IID(nsISimpleEnumerator), (void **)_retval);
+  groupsEnum.forget(_retval);
+  return NS_OK;
 }
 
 /* nsISimpleEnumerator getEnumeratorForGroup (in DOMString aGroup); */
 NS_IMETHODIMP
 nsControllerCommandGroup::GetEnumeratorForGroup(const char *aGroup, nsISimpleEnumerator **_retval)
 {
   nsDependentCString groupKey(aGroup);
   nsTArray<nsCString> *commandList = mGroupsHash.Get(groupKey); // may be null
 
-  nsNamedGroupEnumerator *theGroupEnum = new nsNamedGroupEnumerator(commandList);
-  if (!theGroupEnum) return NS_ERROR_OUT_OF_MEMORY;
+  nsRefPtr<nsNamedGroupEnumerator> theGroupEnum = new nsNamedGroupEnumerator(commandList);
 
-  return theGroupEnum->QueryInterface(NS_GET_IID(nsISimpleEnumerator), (void **)_retval);
+  theGroupEnum.forget(_retval);
+  return NS_OK;
 }
 
 #if 0
 #pragma mark -
 #endif

--- a/embedding/components/find/nsWebBrowserFind.cpp
+++ b/embedding/components/find/nsWebBrowserFind.cpp
@@ -404,26 +404,27 @@ nsresult nsWebBrowserFind::GetRootNode(n
   nsCOMPtr<nsIDOMHTMLDocument> htmlDoc = do_QueryInterface(aDomDoc);
   if (htmlDoc)
   {
     // For HTML documents, the content root node is the body.
     nsCOMPtr<nsIDOMHTMLElement> bodyElement;
     rv = htmlDoc->GetBody(getter_AddRefs(bodyElement));
     NS_ENSURE_SUCCESS(rv, rv);
     NS_ENSURE_ARG_POINTER(bodyElement);
-    return bodyElement->QueryInterface(NS_GET_IID(nsIDOMNode),
-                                       (void **)aNode);
+    bodyElement.forget(aNode);
+    return NS_OK;
   }
 
   // For non-HTML documents, the content root node will be the doc element.
   nsCOMPtr<nsIDOMElement> docElement;
   rv = aDomDoc->GetDocumentElement(getter_AddRefs(docElement));
   NS_ENSURE_SUCCESS(rv, rv);
   NS_ENSURE_ARG_POINTER(docElement);
-  return docElement->QueryInterface(NS_GET_IID(nsIDOMNode), (void **)aNode);
+  docElement.forget(aNode);
+  return NS_OK;
 }
 
 nsresult nsWebBrowserFind::SetRangeAroundDocument(nsIDOMRange* aSearchRange,
                                                   nsIDOMRange* aStartPt,
                                                   nsIDOMRange* aEndPt,
                                                   nsIDOMDocument* aDoc)
 {
     nsCOMPtr<nsIDOMNode> bodyNode;

--- a/intl/strres/nsStringBundle.cpp
+++ b/intl/strres/nsStringBundle.cpp
@@ -646,19 +646,18 @@ nsStringBundleService::CreateExtensibleB
 
   nsRefPtr<nsExtensibleStringBundle> bundle = new nsExtensibleStringBundle();
 
   nsresult res = bundle->Init(aCategory, this);
   if (NS_FAILED(res)) {
     return res;
   }
 
-  res = bundle->QueryInterface(NS_GET_IID(nsIStringBundle), (void**) aResult);
-
-  return res;
+  bundle.forget(aResult);
+  return NS_OK;
 }
 
 #define GLOBAL_PROPERTIES "chrome://global/locale/global-strres.properties"
 
 nsresult
 nsStringBundleService::FormatWithBundle(nsIStringBundle* bundle, nsresult aStatus,
                                         uint32_t argCount, char16_t** argArray,
                                         char16_t* *result)

--- a/security/manager/ssl/src/PSMContentListener.cpp
+++ b/security/manager/ssl/src/PSMContentListener.cpp
@@ -265,27 +265,23 @@ PSMContentListener::CanHandleContent(con
 
 NS_IMETHODIMP
 PSMContentListener::DoContent(const nsACString & aContentType,
                                bool aIsContentPreferred,
                                nsIRequest * aRequest,
                                nsIStreamListener ** aContentHandler,
                                bool * aAbortProcess)
 {
-  PSMContentDownloader *downLoader;
   uint32_t type;
   type = getPSMContentType(PromiseFlatCString(aContentType).get());
   PR_LOG(gPIPNSSLog, PR_LOG_DEBUG, ("PSMContentListener::DoContent\n"));
   if (type != PSMContentDownloader::UNKNOWN_TYPE) {
-    downLoader = new PSMContentDownloader(type);
-    if (downLoader) {
-      downLoader->QueryInterface(NS_GET_IID(nsIStreamListener), 
-                                            (void **)aContentHandler);
-      return NS_OK;
-    }
+    nsRefPtr<PSMContentDownloader> downLoader = new PSMContentDownloader(type);
+    downLoader.forget(aContentHandler);
+    return NS_OK;
   }
   return NS_ERROR_FAILURE;
 }
 
 NS_IMETHODIMP
 PSMContentListener::GetLoadCookie(nsISupports * *aLoadCookie)
 {
   *aLoadCookie = mLoadCookie;

--- a/toolkit/components/places/nsNavHistoryResult.cpp
+++ b/toolkit/components/places/nsNavHistoryResult.cpp
@@ -4318,18 +4318,19 @@ nsNavHistoryResult::SetSuppressNotificat
 NS_IMETHODIMP
 nsNavHistoryResult::GetRoot(nsINavHistoryContainerResultNode** aRoot)
 {
   if (!mRootNode) {
     NS_NOTREACHED("Root is null");
     *aRoot = nullptr;
     return NS_ERROR_FAILURE;
   }
-  return mRootNode->QueryInterface(NS_GET_IID(nsINavHistoryContainerResultNode),
-                                   reinterpret_cast<void**>(aRoot));
+  nsRefPtr<nsNavHistoryContainerResultNode> node(mRootNode);
+  node.forget(aRoot);
+  return NS_OK;
 }
 
 
 void
 nsNavHistoryResult::requestRefresh(nsNavHistoryContainerResultNode* aContainer)
 {
   // Don't add twice the same container.
   if (mRefreshParticipants.IndexOf(aContainer) == mRefreshParticipants.NoIndex)

--- a/widget/nsPrintSettingsImpl.cpp
+++ b/widget/nsPrintSettingsImpl.cpp
@@ -1105,18 +1105,19 @@ nsPrintSettings::GetPageRanges(nsTArray<
 {
   aPages.Clear();
   return NS_OK;
 }
 
 nsresult 
 nsPrintSettings::_Clone(nsIPrintSettings **_retval)
 {
-  nsPrintSettings* printSettings = new nsPrintSettings(*this);
-  return printSettings->QueryInterface(NS_GET_IID(nsIPrintSettings), (void**)_retval); // ref counts
+  nsRefPtr<nsPrintSettings> printSettings = new nsPrintSettings(*this);
+  printSettings.forget(_retval);
+  return NS_OK;
 }
 
 /* nsIPrintSettings clone (); */
 NS_IMETHODIMP 
 nsPrintSettings::Clone(nsIPrintSettings **_retval)
 {
   NS_ENSURE_ARG_POINTER(_retval);
   return _Clone(_retval);

--- a/widget/windows/nsImageClipboard.cpp
+++ b/widget/windows/nsImageClipboard.cpp
@@ -1,9 +1,9 @@
-/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
  
 #include "nsImageClipboard.h"
 
 #include "gfxUtils.h"
 #include "mozilla/gfx/2D.h"
@@ -246,18 +246,19 @@ nsImageFromClipboard ::GetEncodedImageSt
       if (strcmp(aMIMEFormat, kJPGImageMime) == 0)
         encoderCID.AppendLiteral("image/jpeg");
       else
         encoderCID.Append(aMIMEFormat);
       nsCOMPtr<imgIEncoder> encoder = do_CreateInstance(encoderCID.get(), &rv);
       if (NS_SUCCEEDED(rv)){
         rv = encoder->InitFromData(rgbData, 0, width, height, 3 * width /* RGB * # pixels in a row */, 
                                    imgIEncoder::INPUT_FORMAT_RGB, EmptyString());
-        if (NS_SUCCEEDED(rv))
-          encoder->QueryInterface(NS_GET_IID(nsIInputStream), (void **) aInputStream);
+        if (NS_SUCCEEDED(rv)) {
+          encoder.forget(aInputStream);
+        }
       }
     }
     delete [] rgbData;
   } 
   else 
     rv = NS_ERROR_OUT_OF_MEMORY;
 
   return rv;

--- a/widget/windows/nsPrintSettingsWin.cpp
+++ b/widget/windows/nsPrintSettingsWin.cpp
@@ -113,18 +113,19 @@ NS_IMETHODIMP nsPrintSettingsWin::SetDev
   }
   return NS_OK;
 }
 
 //-------------------------------------------
 nsresult 
 nsPrintSettingsWin::_Clone(nsIPrintSettings **_retval)
 {
-  nsPrintSettingsWin* printSettings = new nsPrintSettingsWin(*this);
-  return printSettings->QueryInterface(NS_GET_IID(nsIPrintSettings), (void**)_retval); // ref counts
+  nsRefPtr<nsPrintSettingsWin> printSettings = new nsPrintSettingsWin(*this);
+  printSettings.forget(_retval);
+  return NS_OK;
 }
 
 //-------------------------------------------
 nsPrintSettingsWin& nsPrintSettingsWin::operator=(const nsPrintSettingsWin& rhs)
 {
   if (this == &rhs) {
     return *this;
   }

--- a/xpcom/io/nsAppFileLocationProvider.cpp
+++ b/xpcom/io/nsAppFileLocationProvider.cpp
@@ -223,17 +223,18 @@ nsAppFileLocationProvider::GetFile(const
     }
   } else if (nsCRT::strcmp(aProp, NS_APP_INSTALL_CLEANUP_DIR) == 0) {
     // This is cloned so that embeddors will have a hook to override
     // with their own cleanup dir.  See bugzilla bug #105087
     rv = CloneMozBinDirectory(getter_AddRefs(localFile));
   }
 
   if (localFile && NS_SUCCEEDED(rv)) {
-    return localFile->QueryInterface(NS_GET_IID(nsIFile), (void**)aResult);
+    localFile.forget(aResult);
+    return NS_OK;
   }
 
   return rv;
 }
 
 
 NS_METHOD
 nsAppFileLocationProvider::CloneMozBinDirectory(nsIFile** aLocalFile)

--- a/xpfe/appshell/nsWindowMediator.cpp
+++ b/xpfe/appshell/nsWindowMediator.cpp
@@ -190,35 +190,31 @@ nsWindowMediator::GetInfoFor(nsIWidget *
 
 NS_IMETHODIMP
 nsWindowMediator::GetEnumerator(const char16_t* inType, nsISimpleEnumerator** outEnumerator)
 {
   MOZ_RELEASE_ASSERT(NS_IsMainThread());
   NS_ENSURE_ARG_POINTER(outEnumerator);
   NS_ENSURE_STATE(mReady);
 
-  nsAppShellWindowEnumerator *enumerator = new nsASDOMWindowEarlyToLateEnumerator(inType, *this);
-  if (enumerator)
-    return enumerator->QueryInterface(NS_GET_IID(nsISimpleEnumerator) , (void**)outEnumerator);
-
-  return NS_ERROR_OUT_OF_MEMORY;
+  nsRefPtr<nsAppShellWindowEnumerator> enumerator = new nsASDOMWindowEarlyToLateEnumerator(inType, *this);
+  enumerator.forget(outEnumerator);
+  return NS_OK;
 }
 
 NS_IMETHODIMP
 nsWindowMediator::GetXULWindowEnumerator(const char16_t* inType, nsISimpleEnumerator** outEnumerator)
 {
   MOZ_RELEASE_ASSERT(NS_IsMainThread());
   NS_ENSURE_ARG_POINTER(outEnumerator);
   NS_ENSURE_STATE(mReady);
 
-  nsAppShellWindowEnumerator *enumerator = new nsASXULWindowEarlyToLateEnumerator(inType, *this);
-  if (enumerator)
-    return enumerator->QueryInterface(NS_GET_IID(nsISimpleEnumerator) , (void**)outEnumerator);
-
-  return NS_ERROR_OUT_OF_MEMORY;
+  nsRefPtr<nsAppShellWindowEnumerator> enumerator = new nsASXULWindowEarlyToLateEnumerator(inType, *this);
+  enumerator.forget(outEnumerator);
+  return NS_OK;
 }
 
 NS_IMETHODIMP
 nsWindowMediator::GetZOrderDOMWindowEnumerator(
             const char16_t *aWindowType, bool aFrontToBack,
             nsISimpleEnumerator **_retval)
 {
   MOZ_RELEASE_ASSERT(NS_IsMainThread());