diff --git a/mozilla/view/public/nsIView.h b/mozilla/view/public/nsIView.h
index 14678fe98c4..4b435ea4fa7 100644
--- a/mozilla/view/public/nsIView.h
+++ b/mozilla/view/public/nsIView.h
@@ -452,6 +452,14 @@ public:
    */
   NS_IMETHOD GetScratchPoint(nsPoint **aPoint) = 0;
 
+  /**
+   * Get the extents of the view tree from 'this' down.
+   * 'this' is the coordinate system origin.
+   * @param aExtents out paramemter for extents
+   * @return error status
+   */
+  NS_IMETHOD GetExtents(nsRect *aExtents) = 0;
+
 private:
   NS_IMETHOD_(nsrefcnt) AddRef(void) = 0;
   NS_IMETHOD_(nsrefcnt) Release(void) = 0;
diff --git a/mozilla/view/src/nsView.cpp b/mozilla/view/src/nsView.cpp
index 9216be74069..edd23caa8da 100644
--- a/mozilla/view/src/nsView.cpp
+++ b/mozilla/view/src/nsView.cpp
@@ -1371,3 +1371,37 @@ NS_IMETHODIMP nsView :: GetScratchPoint(nsPoint **aPoint)
 
   return NS_OK;
 }
+
+static void calc_extents(nsIView *view, nsRect *extents, nscoord ox, nscoord oy)
+{
+  nsIView *kid;
+  PRInt32 numkids, cnt;
+  nsRect  bounds;
+
+  view->GetChildCount(numkids);
+
+  for (cnt = 0; cnt < numkids; cnt++)
+  {
+    view->GetChild(cnt, kid);
+    kid->GetBounds(bounds);
+
+    bounds.x += ox;
+    bounds.y += oy;
+
+    extents->IntersectRect(*extents, bounds);
+
+    calc_extents(kid, extents, bounds.x, bounds.y);
+  }
+}
+
+NS_IMETHODIMP nsView :: GetExtents(nsRect *aExtents)
+{
+  GetBounds(*aExtents);
+
+  aExtents->x = 0;
+  aExtents->y = 0;
+
+  calc_extents(this, aExtents, 0, 0);
+
+  return NS_OK;
+}
diff --git a/mozilla/view/src/nsView.h b/mozilla/view/src/nsView.h
index 4ef2573dca3..5f1da5e4f56 100644
--- a/mozilla/view/src/nsView.h
+++ b/mozilla/view/src/nsView.h
@@ -97,6 +97,7 @@ public:
   NS_IMETHOD ClearViewFlags(PRUint32 aFlags);
   NS_IMETHOD GetViewFlags(PRUint32 *aFlags);
   NS_IMETHOD GetScratchPoint(nsPoint **aPoint);
+  NS_IMETHOD GetExtents(nsRect *aExtents);
 
   // Helper function to get the view that's associated with a widget
   static nsIView*  GetViewFor(nsIWidget* aWidget);