diff --git a/content/base/public/Element.h b/content/base/public/Element.h
index 5de69f7ad37..7e7e0779d95 100644
--- a/content/base/public/Element.h
+++ b/content/base/public/Element.h
@@ -18,7 +18,6 @@
 #include "nsEventStates.h"                 // for member
 #include "mozilla/dom/DirectionalityUtils.h"
 #include "nsIDOMElement.h"
-#include "nsIDOMDocumentFragment.h"
 #include "nsILinkHandler.h"
 #include "nsNodeUtils.h"
 #include "nsAttrAndChildArray.h"
diff --git a/content/base/src/Attr.cpp b/content/base/src/Attr.cpp
index 0de6cb5ec7e..70b0027ba29 100644
--- a/content/base/src/Attr.cpp
+++ b/content/base/src/Attr.cpp
@@ -18,7 +18,6 @@
 #include "nsDOMString.h"
 #include "nsIContentInlines.h"
 #include "nsIDocument.h"
-#include "nsIDOMDocument.h"
 #include "nsIDOMUserDataHandler.h"
 #include "nsEventDispatcher.h"
 #include "nsGkAtoms.h"
diff --git a/content/base/src/FragmentOrElement.cpp b/content/base/src/FragmentOrElement.cpp
index c012ffab950..bb8077958da 100644
--- a/content/base/src/FragmentOrElement.cpp
+++ b/content/base/src/FragmentOrElement.cpp
@@ -24,7 +24,6 @@
 #include "nsIDocumentInlines.h"
 #include "nsIDocumentEncoder.h"
 #include "nsIDOMNodeList.h"
-#include "nsIDOMDocument.h"
 #include "nsIContentIterator.h"
 #include "nsEventListenerManager.h"
 #include "nsFocusManager.h"
@@ -87,7 +86,6 @@
 
 #include "nsNodeInfoManager.h"
 #include "nsICategoryManager.h"
-#include "nsIDOMDocumentType.h"
 #include "nsIDOMUserDataHandler.h"
 #include "nsGenericHTMLElement.h"
 #include "nsIEditor.h"
@@ -2704,18 +2702,15 @@ FragmentOrElement::SetInnerHTMLInternal(const nsAString& aInnerHTML, ErrorResult
     nsContentUtils::FireMutationEventsForDirectParsing(doc, target,
                                                        oldChildCount);
   } else {
-    nsCOMPtr<nsIDOMDocumentFragment> df;
-    aError = nsContentUtils::CreateContextualFragment(target, aInnerHTML,
-                                                      true,
-                                                      getter_AddRefs(df));
-    nsCOMPtr<nsINode> fragment = do_QueryInterface(df);
+    nsRefPtr<DocumentFragment> df =
+      nsContentUtils::CreateContextualFragment(target, aInnerHTML, true, aError);
     if (!aError.Failed()) {
       // Suppress assertion about node removal mutation events that can't have
       // listeners anyway, because no one has had the chance to register mutation
       // listeners on the fragment that comes from the parser.
       nsAutoScriptBlockerSuppressNodeRemoved scriptBlocker;
 
-      static_cast<nsINode*>(target)->AppendChild(*fragment, aError);
+      static_cast<nsINode*>(target)->AppendChild(*df, aError);
       mb.NodesAdded();
     }
   }
diff --git a/content/base/src/nsContentAreaDragDrop.cpp b/content/base/src/nsContentAreaDragDrop.cpp
index 89befa69608..5a823123a95 100644
--- a/content/base/src/nsContentAreaDragDrop.cpp
+++ b/content/base/src/nsContentAreaDragDrop.cpp
@@ -21,7 +21,6 @@
 #include "nsIDOMEvent.h"
 #include "nsIDOMDragEvent.h"
 #include "nsPIDOMWindow.h"
-#include "nsIDOMDocument.h"
 #include "nsIDOMRange.h"
 #include "nsIFormControl.h"
 #include "nsIDOMHTMLAreaElement.h"
@@ -52,6 +51,7 @@
 #include "imgIRequest.h"
 #include "nsDOMDataTransfer.h"
 #include "nsIMIMEInfo.h"
+#include "nsRange.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/HTMLAreaElement.h"
 
@@ -339,20 +339,17 @@ void
 DragDataProducer::GetNodeString(nsIContent* inNode,
                                 nsAString & outNodeString)
 {
-  nsCOMPtr<nsIDOMNode> node = do_QueryInterface(inNode);
+  nsCOMPtr<nsINode> node = inNode;
 
   outNodeString.Truncate();
 
   // use a range to get the text-equivalent of the node
-  nsCOMPtr<nsIDOMDocument> doc;
-  node->GetOwnerDocument(getter_AddRefs(doc));
-  if (doc) {
-    nsCOMPtr<nsIDOMRange> range;
-    doc->CreateRange(getter_AddRefs(range));
-    if (range) {
-      range->SelectNode(node);
-      range->ToString(outNodeString);
-    }
+  nsCOMPtr<nsIDocument> doc = node->OwnerDoc();
+  mozilla::ErrorResult rv;
+  nsRefPtr<nsRange> range = doc->CreateRange(rv);
+  if (range) {
+    range->SelectNode(*node, rv);
+    range->ToString(outNodeString);
   }
 }
 
diff --git a/content/base/src/nsCopySupport.cpp b/content/base/src/nsCopySupport.cpp
index 450d77b2b70..fa43c632643 100644
--- a/content/base/src/nsCopySupport.cpp
+++ b/content/base/src/nsCopySupport.cpp
@@ -67,7 +67,7 @@ static nsresult AppendString(nsITransferable *aTransferable,
 
 // copy HTML node data
 static nsresult AppendDOMNode(nsITransferable *aTransferable,
-                              nsIDOMNode *aDOMNode);
+                              nsINode* aDOMNode);
 
 // Helper used for HTMLCopy and GetTransferableForSelection since both routines
 // share common code.
@@ -421,7 +421,7 @@ nsCopySupport::ImageCopy(nsIImageLoadingContent* aImageElement,
 
   if (aCopyFlags & nsIContentViewerEdit::COPY_IMAGE_HTML) {
     // append HTML data to the transferable
-    nsCOMPtr<nsIDOMNode> node(do_QueryInterface(aImageElement, &rv));
+    nsCOMPtr<nsINode> node(do_QueryInterface(aImageElement, &rv));
     NS_ENSURE_SUCCESS(rv, rv);
 
     rv = AppendDOMNode(trans, node);
@@ -486,37 +486,33 @@ static nsresult AppendString(nsITransferable *aTransferable,
 }
 
 static nsresult AppendDOMNode(nsITransferable *aTransferable,
-                              nsIDOMNode *aDOMNode)
+                              nsINode *aDOMNode)
 {
   nsresult rv;
-  
+
   // selializer
   nsCOMPtr<nsIDocumentEncoder>
     docEncoder(do_CreateInstance(NS_HTMLCOPY_ENCODER_CONTRACTID, &rv));
   NS_ENSURE_SUCCESS(rv, rv);
 
   // get document for the encoder
-  nsCOMPtr<nsIDOMDocument> domDocument;
-  rv = aDOMNode->GetOwnerDocument(getter_AddRefs(domDocument));
-  NS_ENSURE_SUCCESS(rv, rv);
-  nsCOMPtr<nsIDocument> document(do_QueryInterface(domDocument, &rv));
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsIDocument> document = aDOMNode->OwnerDoc();
 
   // Note that XHTML is not counted as HTML here, because we can't copy it
   // properly (all the copy code for non-plaintext assumes using HTML
   // serializers and parsers is OK, and those mess up XHTML).
-  nsCOMPtr<nsIHTMLDocument> htmlDoc = do_QueryInterface(domDocument, &rv);
+  nsCOMPtr<nsIHTMLDocument> htmlDoc = do_QueryInterface(document, &rv);
   NS_ENSURE_SUCCESS(rv, NS_OK);
 
   NS_ENSURE_TRUE(document->IsHTML(), NS_OK);
 
   // init encoder with document and node
-  rv = docEncoder->Init(domDocument, NS_LITERAL_STRING(kHTMLMime),
-                        nsIDocumentEncoder::OutputAbsoluteLinks |
-                        nsIDocumentEncoder::OutputEncodeW3CEntities);
+  rv = docEncoder->NativeInit(document, NS_LITERAL_STRING(kHTMLMime),
+                              nsIDocumentEncoder::OutputAbsoluteLinks |
+                              nsIDocumentEncoder::OutputEncodeW3CEntities);
   NS_ENSURE_SUCCESS(rv, rv);
 
-  rv = docEncoder->SetNode(aDOMNode);
+  rv = docEncoder->SetNativeNode(aDOMNode);
   NS_ENSURE_SUCCESS(rv, rv);
 
   // serialize to string
diff --git a/content/base/src/nsDOMAttributeMap.cpp b/content/base/src/nsDOMAttributeMap.cpp
index b7a0fe7911b..a2c327aa2d4 100644
--- a/content/base/src/nsDOMAttributeMap.cpp
+++ b/content/base/src/nsDOMAttributeMap.cpp
@@ -18,7 +18,6 @@
 #include "nsError.h"
 #include "nsIContentInlines.h"
 #include "nsIDocument.h"
-#include "nsIDOMDocument.h"
 #include "nsINameSpaceManager.h"
 #include "nsNodeInfoManager.h"
 #include "nsUnicharUtils.h"
diff --git a/content/base/src/nsDataDocumentContentPolicy.cpp b/content/base/src/nsDataDocumentContentPolicy.cpp
index 6233dcdf443..6d2662dc6f0 100644
--- a/content/base/src/nsDataDocumentContentPolicy.cpp
+++ b/content/base/src/nsDataDocumentContentPolicy.cpp
@@ -15,7 +15,6 @@
 #include "nsIDocument.h"
 #include "nsINode.h"
 #include "nsIDOMWindow.h"
-#include "nsIDOMDocument.h"
 
 NS_IMPL_ISUPPORTS1(nsDataDocumentContentPolicy, nsIContentPolicy)
 
@@ -50,11 +49,9 @@ nsDataDocumentContentPolicy::ShouldLoad(uint32_t aContentType,
   if (node) {
     doc = node->OwnerDoc();
   } else {
-    nsCOMPtr<nsIDOMWindow> window = do_QueryInterface(aRequestingContext);
+    nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(aRequestingContext);
     if (window) {
-      nsCOMPtr<nsIDOMDocument> domDoc;
-      window->GetDocument(getter_AddRefs(domDoc));
-      doc = do_QueryInterface(domDoc);
+      doc = window->GetDoc();
     }
   }
 
diff --git a/content/base/src/nsFrameLoader.cpp b/content/base/src/nsFrameLoader.cpp
index 31cb80ab9b1..cfc1ec4d439 100644
--- a/content/base/src/nsFrameLoader.cpp
+++ b/content/base/src/nsFrameLoader.cpp
@@ -627,8 +627,7 @@ static void
 FirePageHideEvent(nsIDocShellTreeItem* aItem,
                   EventTarget* aChromeEventHandler)
 {
-  nsCOMPtr<nsIDOMDocument> doc = do_GetInterface(aItem);
-  nsCOMPtr<nsIDocument> internalDoc = do_QueryInterface(doc);
+  nsCOMPtr<nsIDocument> internalDoc = do_GetInterface(aItem);
   NS_ASSERTION(internalDoc, "What happened here?");
   internalDoc->OnPageHide(true, aChromeEventHandler);
 
@@ -670,8 +669,7 @@ FirePageShowEvent(nsIDocShellTreeItem* aItem,
     }
   }
 
-  nsCOMPtr<nsIDOMDocument> doc = do_GetInterface(aItem);
-  nsCOMPtr<nsIDocument> internalDoc = do_QueryInterface(doc);
+  nsCOMPtr<nsIDocument> internalDoc = do_GetInterface(aItem);
   NS_ASSERTION(internalDoc, "What happened here?");
   if (internalDoc->IsShowing() == aFireIfShowing) {
     internalDoc->OnPageShow(true, aChromeEventHandler);
@@ -2195,16 +2193,14 @@ nsFrameLoader::CreateStaticClone(nsIFrameLoader* aDest)
   dest->MaybeCreateDocShell();
   NS_ENSURE_STATE(dest->mDocShell);
 
-  nsCOMPtr<nsIDOMDocument> dummy = do_GetInterface(dest->mDocShell);
+  nsCOMPtr<nsIDocument> dummy = do_GetInterface(dest->mDocShell);
   nsCOMPtr<nsIContentViewer> viewer;
   dest->mDocShell->GetContentViewer(getter_AddRefs(viewer));
   NS_ENSURE_STATE(viewer);
 
   nsCOMPtr<nsIDocShell> origDocShell;
   GetDocShell(getter_AddRefs(origDocShell));
-  nsCOMPtr<nsIDOMDocument> domDoc = do_GetInterface(origDocShell);
-
-  nsCOMPtr<nsIDocument> doc = do_QueryInterface(domDoc);
+  nsCOMPtr<nsIDocument> doc = do_GetInterface(origDocShell);
   NS_ENSURE_STATE(doc);
   nsCOMPtr<nsIDocument> clonedDoc = doc->CreateStaticClone(dest->mDocShell);
   nsCOMPtr<nsIDOMDocument> clonedDOMDoc = do_QueryInterface(clonedDoc);
diff --git a/content/base/src/nsObjectLoadingContent.cpp b/content/base/src/nsObjectLoadingContent.cpp
index e2f3749ad22..adde762e4fa 100644
--- a/content/base/src/nsObjectLoadingContent.cpp
+++ b/content/base/src/nsObjectLoadingContent.cpp
@@ -75,6 +75,7 @@
 #include "nsDOMClassInfo.h"
 #include "nsWrapperCacheInlines.h"
 #include "nsDOMJSUtils.h"
+#include "nsDOMEvent.h"
 
 #include "nsWidgetsCID.h"
 #include "nsContentCID.h"
@@ -297,17 +298,16 @@ nsPluginCrashedEvent::Run()
   LOG(("OBJLC [%p]: Firing plugin crashed event\n",
        mContent.get()));
 
-  nsCOMPtr<nsIDOMDocument> domDoc =
-    do_QueryInterface(mContent->GetDocument());
-  if (!domDoc) {
+  nsCOMPtr<nsIDocument> doc = mContent->GetDocument();
+  if (!doc) {
     NS_WARNING("Couldn't get document for PluginCrashed event!");
     return NS_OK;
   }
 
-  nsCOMPtr<nsIDOMEvent> event;
-  domDoc->CreateEvent(NS_LITERAL_STRING("datacontainerevents"),
-                      getter_AddRefs(event));
-  nsCOMPtr<nsIDOMDataContainerEvent> containerEvent(do_QueryInterface(event));
+  ErrorResult rv;
+  nsRefPtr<nsDOMEvent> event =
+    doc->CreateEvent(NS_LITERAL_STRING("datacontainerevents"), rv);
+  nsCOMPtr<nsIDOMDataContainerEvent> containerEvent(do_QueryObject(event));
   if (!containerEvent) {
     NS_WARNING("Couldn't QI event for PluginCrashed event!");
     return NS_OK;