diff --git a/mozilla/layout/generic/nsHTMLContainerFrame.cpp b/mozilla/layout/generic/nsHTMLContainerFrame.cpp
index e2c1702e012..908ca036b1f 100644
--- a/mozilla/layout/generic/nsHTMLContainerFrame.cpp
+++ b/mozilla/layout/generic/nsHTMLContainerFrame.cpp
@@ -322,6 +322,75 @@ nsHTMLContainerFrame::MoveFrameOutOfFlow(nsIPresContext&        aPresContext,
   return PR_FALSE;
 }
 
+//XXX handle replace reflow command
+NS_METHOD nsHTMLContainerFrame::AddFrame(const nsHTMLReflowState& aReflowState,
+                                         nsIFrame *               aAddedFrame)
+{
+  nsresult rv=NS_OK;
+  nsIReflowCommand::ReflowType type;
+  aReflowState.reflowCommand->GetType(type);
+  // we have a generic frame that gets inserted but doesn't effect reflow
+  // hook it up then ignore it
+  if (nsIReflowCommand::FrameAppended==type)
+  { // frameAppended reflow -- find the last child and make aInsertedFrame its next sibling
+    nsIFrame *lastChild=mFirstChild;
+    nsIFrame *nextChild=mFirstChild;
+    while (nsnull!=nextChild)
+    {
+      lastChild=nextChild;
+      nextChild->GetNextSibling(nextChild);
+    }
+    if (nsnull==lastChild)
+      mFirstChild = aAddedFrame;
+    else
+      lastChild->SetNextSibling(aAddedFrame);
+  }
+  else if (nsIReflowCommand::FrameInserted==type) 
+  { // frameInserted reflow -- hook up aInsertedFrame as prevSibling's next sibling, 
+    // and be sure to hook in aInsertedFrame's nextSibling (from prevSibling)
+    nsIFrame *prevSibling=nsnull;
+    rv = aReflowState.reflowCommand->GetPrevSiblingFrame(prevSibling);
+    if (NS_SUCCEEDED(rv) && (nsnull!=prevSibling))
+    {
+      nsIFrame *nextSibling=nsnull;
+      prevSibling->GetNextSibling(nextSibling);
+      prevSibling->SetNextSibling(aAddedFrame);
+      aAddedFrame->SetNextSibling(nextSibling);
+    }
+    else
+    {
+      nsIFrame *nextSibling = mFirstChild;
+      mFirstChild = aAddedFrame;
+      aAddedFrame->SetNextSibling(nextSibling);
+    }
+  }
+  else
+  {
+    NS_ASSERTION(PR_FALSE, "bad reflow type");
+    rv = NS_ERROR_UNEXPECTED;
+  }
+  return rv;
+}
+  /** */
+NS_METHOD nsHTMLContainerFrame::RemoveFrame(nsIFrame * aRemovedFrame)
+{
+  nsIFrame *prevChild=nsnull;
+  nsIFrame *nextChild=mFirstChild;
+  while (nextChild!=aRemovedFrame)
+  {
+    prevChild=nextChild;
+    nextChild->GetNextSibling(nextChild);
+  }  
+  nextChild=nsnull;
+  aRemovedFrame->GetNextSibling(nextChild);
+  if (nsnull==prevChild)  // objectFrame was first child
+    mFirstChild = nextChild;
+  else
+    prevChild->SetNextSibling(nextChild);
+  return NS_OK;;
+}
+
+
 /**
  * Create a next-in-flow for aFrame. Will return the newly created
  * frame in aNextInFlowResult <b>if and only if</b> a new frame is
diff --git a/mozilla/layout/generic/nsHTMLContainerFrame.h b/mozilla/layout/generic/nsHTMLContainerFrame.h
index 9a51d46909b..5c02a275fda 100644
--- a/mozilla/layout/generic/nsHTMLContainerFrame.h
+++ b/mozilla/layout/generic/nsHTMLContainerFrame.h
@@ -63,6 +63,14 @@ public:
                             const nsStylePosition* aPosition,
                             nsIFrame*&             aPlaceholderFrame);
 
+  /* helper methods for incremental reflow */
+  /** */
+  NS_IMETHOD AddFrame(const nsHTMLReflowState& aReflowState,
+                      nsIFrame *               aAddedFrame);
+  /** */
+  NS_IMETHOD RemoveFrame(nsIFrame * aRemovedFrame);
+
+
   // Helper method to create next-in-flows if necessary
   static nsresult CreateNextInFlow(nsIPresContext& aPresContext,
                                    nsIFrame* aOuterFrame,
diff --git a/mozilla/layout/html/base/src/nsHTMLContainerFrame.cpp b/mozilla/layout/html/base/src/nsHTMLContainerFrame.cpp
index e2c1702e012..908ca036b1f 100644
--- a/mozilla/layout/html/base/src/nsHTMLContainerFrame.cpp
+++ b/mozilla/layout/html/base/src/nsHTMLContainerFrame.cpp
@@ -322,6 +322,75 @@ nsHTMLContainerFrame::MoveFrameOutOfFlow(nsIPresContext&        aPresContext,
   return PR_FALSE;
 }
 
+//XXX handle replace reflow command
+NS_METHOD nsHTMLContainerFrame::AddFrame(const nsHTMLReflowState& aReflowState,
+                                         nsIFrame *               aAddedFrame)
+{
+  nsresult rv=NS_OK;
+  nsIReflowCommand::ReflowType type;
+  aReflowState.reflowCommand->GetType(type);
+  // we have a generic frame that gets inserted but doesn't effect reflow
+  // hook it up then ignore it
+  if (nsIReflowCommand::FrameAppended==type)
+  { // frameAppended reflow -- find the last child and make aInsertedFrame its next sibling
+    nsIFrame *lastChild=mFirstChild;
+    nsIFrame *nextChild=mFirstChild;
+    while (nsnull!=nextChild)
+    {
+      lastChild=nextChild;
+      nextChild->GetNextSibling(nextChild);
+    }
+    if (nsnull==lastChild)
+      mFirstChild = aAddedFrame;
+    else
+      lastChild->SetNextSibling(aAddedFrame);
+  }
+  else if (nsIReflowCommand::FrameInserted==type) 
+  { // frameInserted reflow -- hook up aInsertedFrame as prevSibling's next sibling, 
+    // and be sure to hook in aInsertedFrame's nextSibling (from prevSibling)
+    nsIFrame *prevSibling=nsnull;
+    rv = aReflowState.reflowCommand->GetPrevSiblingFrame(prevSibling);
+    if (NS_SUCCEEDED(rv) && (nsnull!=prevSibling))
+    {
+      nsIFrame *nextSibling=nsnull;
+      prevSibling->GetNextSibling(nextSibling);
+      prevSibling->SetNextSibling(aAddedFrame);
+      aAddedFrame->SetNextSibling(nextSibling);
+    }
+    else
+    {
+      nsIFrame *nextSibling = mFirstChild;
+      mFirstChild = aAddedFrame;
+      aAddedFrame->SetNextSibling(nextSibling);
+    }
+  }
+  else
+  {
+    NS_ASSERTION(PR_FALSE, "bad reflow type");
+    rv = NS_ERROR_UNEXPECTED;
+  }
+  return rv;
+}
+  /** */
+NS_METHOD nsHTMLContainerFrame::RemoveFrame(nsIFrame * aRemovedFrame)
+{
+  nsIFrame *prevChild=nsnull;
+  nsIFrame *nextChild=mFirstChild;
+  while (nextChild!=aRemovedFrame)
+  {
+    prevChild=nextChild;
+    nextChild->GetNextSibling(nextChild);
+  }  
+  nextChild=nsnull;
+  aRemovedFrame->GetNextSibling(nextChild);
+  if (nsnull==prevChild)  // objectFrame was first child
+    mFirstChild = nextChild;
+  else
+    prevChild->SetNextSibling(nextChild);
+  return NS_OK;;
+}
+
+
 /**
  * Create a next-in-flow for aFrame. Will return the newly created
  * frame in aNextInFlowResult <b>if and only if</b> a new frame is
diff --git a/mozilla/layout/html/base/src/nsHTMLContainerFrame.h b/mozilla/layout/html/base/src/nsHTMLContainerFrame.h
index 9a51d46909b..5c02a275fda 100644
--- a/mozilla/layout/html/base/src/nsHTMLContainerFrame.h
+++ b/mozilla/layout/html/base/src/nsHTMLContainerFrame.h
@@ -63,6 +63,14 @@ public:
                             const nsStylePosition* aPosition,
                             nsIFrame*&             aPlaceholderFrame);
 
+  /* helper methods for incremental reflow */
+  /** */
+  NS_IMETHOD AddFrame(const nsHTMLReflowState& aReflowState,
+                      nsIFrame *               aAddedFrame);
+  /** */
+  NS_IMETHOD RemoveFrame(nsIFrame * aRemovedFrame);
+
+
   // Helper method to create next-in-flows if necessary
   static nsresult CreateNextInFlow(nsIPresContext& aPresContext,
                                    nsIFrame* aOuterFrame,