diff --git a/mozilla/gfx/public/nsRect.h b/mozilla/gfx/public/nsRect.h
index e8a9a795612..c30a805ce45 100644
--- a/mozilla/gfx/public/nsRect.h
+++ b/mozilla/gfx/public/nsRect.h
@@ -97,6 +97,7 @@ struct NS_GFX nsRect {
   void MoveTo(nscoord aX, nscoord aY) {x = aX; y = aY;}
   void MoveTo(const nsPoint& aPoint) {x = aPoint.x; y = aPoint.y;}
   void MoveBy(nscoord aDx, nscoord aDy) {x += aDx; y += aDy;}
+  void MoveBy(const nsPoint& aPoint) {x += aPoint.x; y += aPoint.y;}
   void SizeTo(nscoord aWidth, nscoord aHeight) {width = aWidth; height = aHeight;}
   void SizeTo(const nsSize& aSize) {SizeTo(aSize.width, aSize.height);}
   void SizeBy(nscoord aDeltaWidth, nscoord aDeltaHeight) {width += aDeltaWidth;
diff --git a/mozilla/layout/generic/nsFrame.cpp b/mozilla/layout/generic/nsFrame.cpp
index 2e523534fd6..715bc276494 100644
--- a/mozilla/layout/generic/nsFrame.cpp
+++ b/mozilla/layout/generic/nsFrame.cpp
@@ -4352,6 +4352,24 @@ nsFrame::StoreOverflow(nsIPresContext*      aPresContext,
   }   
 }
 
+void
+nsFrame::ConsiderChildOverflow(nsIPresContext* aPresContext,
+                               nsRect&         aOverflowArea,
+                               nsIFrame*       aChildFrame)
+{
+  if (GetStyleDisplay()->mOverflow != NS_STYLE_OVERFLOW_HIDDEN) {
+    nsRect* overflowArea = aChildFrame->GetOverflowAreaProperty(aPresContext);
+    if (overflowArea) {
+      nsRect childOverflow(*overflowArea);
+      childOverflow.MoveBy(aChildFrame->GetPosition());
+      aOverflowArea.UnionRect(aOverflowArea, childOverflow);
+    }
+    else {
+      aOverflowArea.UnionRect(aOverflowArea, aChildFrame->GetRect());
+    }
+  }
+}
+
 NS_IMETHODIMP 
 nsFrame::GetParentStyleContextFrame(nsIPresContext* aPresContext,
                                     nsIFrame**      aProviderFrame,
diff --git a/mozilla/layout/generic/nsFrame.h b/mozilla/layout/generic/nsFrame.h
index 55140a92a11..48b612d6e49 100644
--- a/mozilla/layout/generic/nsFrame.h
+++ b/mozilla/layout/generic/nsFrame.h
@@ -376,6 +376,12 @@ public:
   void StoreOverflow(nsIPresContext*      aPresContext,
                      nsHTMLReflowMetrics& aMetrics);
 
+  // incorporate the child overflow area into the parent overflow area
+  // if the child does not have a overflow use the child area
+  void ConsiderChildOverflow(nsIPresContext* aPresContext,
+                             nsRect&         aOverflowArea,
+                             nsIFrame*       aChildFrame);
+
   //Mouse Capturing code used by the frames to tell the view to capture all the following events
   NS_IMETHOD CaptureMouse(nsIPresContext* aPresContext, PRBool aGrabMouseEvents);
   PRBool   IsMouseCaptured(nsIPresContext* aPresContext);
diff --git a/mozilla/layout/html/base/src/nsFrame.cpp b/mozilla/layout/html/base/src/nsFrame.cpp
index 2e523534fd6..715bc276494 100644
--- a/mozilla/layout/html/base/src/nsFrame.cpp
+++ b/mozilla/layout/html/base/src/nsFrame.cpp
@@ -4352,6 +4352,24 @@ nsFrame::StoreOverflow(nsIPresContext*      aPresContext,
   }   
 }
 
+void
+nsFrame::ConsiderChildOverflow(nsIPresContext* aPresContext,
+                               nsRect&         aOverflowArea,
+                               nsIFrame*       aChildFrame)
+{
+  if (GetStyleDisplay()->mOverflow != NS_STYLE_OVERFLOW_HIDDEN) {
+    nsRect* overflowArea = aChildFrame->GetOverflowAreaProperty(aPresContext);
+    if (overflowArea) {
+      nsRect childOverflow(*overflowArea);
+      childOverflow.MoveBy(aChildFrame->GetPosition());
+      aOverflowArea.UnionRect(aOverflowArea, childOverflow);
+    }
+    else {
+      aOverflowArea.UnionRect(aOverflowArea, aChildFrame->GetRect());
+    }
+  }
+}
+
 NS_IMETHODIMP 
 nsFrame::GetParentStyleContextFrame(nsIPresContext* aPresContext,
                                     nsIFrame**      aProviderFrame,
diff --git a/mozilla/layout/html/base/src/nsFrame.h b/mozilla/layout/html/base/src/nsFrame.h
index 55140a92a11..48b612d6e49 100644
--- a/mozilla/layout/html/base/src/nsFrame.h
+++ b/mozilla/layout/html/base/src/nsFrame.h
@@ -376,6 +376,12 @@ public:
   void StoreOverflow(nsIPresContext*      aPresContext,
                      nsHTMLReflowMetrics& aMetrics);
 
+  // incorporate the child overflow area into the parent overflow area
+  // if the child does not have a overflow use the child area
+  void ConsiderChildOverflow(nsIPresContext* aPresContext,
+                             nsRect&         aOverflowArea,
+                             nsIFrame*       aChildFrame);
+
   //Mouse Capturing code used by the frames to tell the view to capture all the following events
   NS_IMETHOD CaptureMouse(nsIPresContext* aPresContext, PRBool aGrabMouseEvents);
   PRBool   IsMouseCaptured(nsIPresContext* aPresContext);