--- a/layout/base/nsIPresShell.h
+++ b/layout/base/nsIPresShell.h
@@ -134,18 +134,18 @@ typedef struct CapturingContentInfo {
   // capture should only be allowed during a mousedown event
   PRPackedBool mAllowed;
   PRPackedBool mRetargetToElement;
   PRPackedBool mPreventDrag;
   nsIContent* mContent;
 } CapturingContentInfo;
 
 #define NS_IPRESSHELL_IID     \
-  { 0xfd4ba6e3, 0x921c, 0x4058, \
-    { 0xa6, 0x1b, 0xc7, 0x14, 0x5e, 0x80, 0x50, 0x1f } }
+ { 0x3a8030b5, 0x8d2c, 0x4cb3, \
+    { 0xb5, 0xae, 0xb2, 0x43, 0xa9, 0x28, 0x02, 0x82 } }
 
 // Constants for ScrollContentIntoView() function
 #define NS_PRESSHELL_SCROLL_TOP      0
 #define NS_PRESSHELL_SCROLL_BOTTOM   100
 #define NS_PRESSHELL_SCROLL_LEFT     0
 #define NS_PRESSHELL_SCROLL_RIGHT    100
 #define NS_PRESSHELL_SCROLL_CENTER   50
 #define NS_PRESSHELL_SCROLL_ANYWHERE -1
@@ -568,18 +568,17 @@ public:
   virtual NS_HIDDEN_(nsresult) ScrollContentIntoView(nsIContent* aContent,
                                                      PRIntn      aVPercent,
                                                      PRIntn      aHPercent,
                                                      PRUint32    aFlags) = 0;
 
   enum {
     SCROLL_FIRST_ANCESTOR_ONLY = 0x01,
     SCROLL_OVERFLOW_HIDDEN = 0x02,
-    SCROLL_NO_PARENT_FRAMES = 0x04,
-    SCROLL_ALLOW_SMOOTH = 0x08
+    SCROLL_NO_PARENT_FRAMES = 0x04
   };
   /**
    * Scrolls the view of the document so that the given area of a frame
    * is visible, if possible. Layout is not flushed before scrolling.
    * 
    * @param aRect relative to aFrame
    * @param aVPercent see ScrollContentIntoView
    * @param aHPercent see ScrollContentIntoView

--- a/layout/base/nsPresShell.cpp
+++ b/layout/base/nsPresShell.cpp
@@ -219,18 +219,17 @@
   NS_TIME_FUNCTION_DECLARE_DOCURL                      \
   NS_TIME_FUNCTION_MIN_FMT(1.0,                        \
      "%s (line %d) (document: %s)", MOZ_FUNCTION_NAME, \
      __LINE__, docURL__.get())
 #else
 #define NS_TIME_FUNCTION_WITH_DOCURL do{} while(0)
 #endif
 
-static const PRUint32 ANCHOR_SCROLL_FLAGS =
-    SCROLL_OVERFLOW_HIDDEN | SCROLL_NO_PARENT_FRAMES | SCROLL_ALLOW_SMOOTH;
+#define ANCHOR_SCROLL_FLAGS (SCROLL_OVERFLOW_HIDDEN | SCROLL_NO_PARENT_FRAMES)
 
 #include "nsContentCID.h"
 static NS_DEFINE_IID(kRangeCID,     NS_RANGE_CID);
 
 /* for NS_MEMORY_REPORTER_IMPLEMENT */
 #include "nsIMemoryReporter.h"
 
 using namespace mozilla;
@@ -1190,19 +1189,18 @@ protected:
 
   // Set of frames that we should mark with NS_FRAME_HAS_DIRTY_CHILDREN after
   // we finish reflowing mCurrentReflowRoot.
   nsTHashtable< nsPtrHashKey<nsIFrame> > mFramesToDirty;
 
   // Information needed to properly handle scrolling content into view if the
   // pre-scroll reflow flush can be interrupted.  mContentToScrollTo is
   // non-null between the initial scroll attempt and the first time we finish
-  // processing all our dirty roots.  mContentScrollVPosition,
-  // mContentScrollHPosition and mContentToScrollToFlags are only used when
-  // it's non-null.
+  // processing all our dirty roots.  mContentScrollVPosition and
+  // mContentScrollHPosition are only used when it's non-null.
   nsCOMPtr<nsIContent> mContentToScrollTo;
   PRIntn mContentScrollVPosition;
   PRIntn mContentScrollHPosition;
   PRUint32 mContentToScrollToFlags;
 
   class nsDelayedEvent
   {
   public:
@@ -4146,19 +4144,17 @@ static void ScrollToShowRect(nsIScrollab
       // Align the frame edge according to the specified percentage
       nscoord frameAlignX =
         NSToCoordRound(aRect.x + (aRect.width) * (aHPercent / 100.0f));
       scrollPt.x =
         NSToCoordRound(frameAlignX - visibleRect.width * (aHPercent / 100.0f));
     }
   }
 
-  aScrollFrame->ScrollTo(scrollPt,
-      (aFlags & nsIPresShell::SCROLL_ALLOW_SMOOTH) ? nsIScrollableFrame::SMOOTH :
-                                                     nsIScrollableFrame::INSTANT);
+  aScrollFrame->ScrollTo(scrollPt, nsIScrollableFrame::INSTANT);
 }
 
 nsresult
 PresShell::ScrollContentIntoView(nsIContent* aContent,
                                  PRIntn      aVPercent,
                                  PRIntn      aHPercent,
                                  PRUint32    aFlags)
 {