Tweaks to the scrollbar.

layout/xul/base/src/nsIScrollbarListener.h

@@ -34,8 +34,7 @@ public:
   
   NS_IMETHOD PositionChanged(PRInt32 aOldIndex, PRInt32 aNewIndex) = 0;
 
-  NS_IMETHOD PagedUp() = 0;
-  NS_IMETHOD PagedDown() = 0;
+  NS_IMETHOD PagedUpDown() = 0;
 };
 
 #endif

layout/xul/base/src/nsSliderFrame.cpp

@@ -48,7 +48,7 @@
 #include "nsDocument.h"
 #include "nsTitledButtonFrame.h"
 #include "nsScrollbarButtonFrame.h"
-
+#include "nsIScrollbarListener.h"
 
 nsresult
 NS_NewSliderFrame ( nsIFrame** aNewFrame )
@@ -68,6 +68,7 @@ NS_NewSliderFrame ( nsIFrame** aNewFrame )
 
 
 nsSliderFrame::nsSliderFrame()
+:mScrollbarListener(nsnull), mCurPos(0)
 {
 }
 
@@ -455,6 +456,10 @@ nsSliderFrame::PageUpDown(nsIPresContext& aPresContext, nsIFrame* aThumbFrame, n
   // asking it for the current position and the page increment. If we are not in a scrollbar we will
   // get the values from our own node.
   nsIContent* scrollbar = GetScrollBar();
+  
+  if (mScrollbarListener)
+    mScrollbarListener->PagedUpDown(); // Let the listener decide our increment.
+
   nscoord pageIncrement = GetPageIncrement(scrollbar);
   PRInt32 curpos = GetCurrentPosition(scrollbar);
   SetCurrentPosition(aPresContext, scrollbar, aThumbFrame, curpos + change*pageIncrement);
@@ -516,6 +521,12 @@ nsSliderFrame::CurrentPositionChanged(nsIPresContext* aPresContext)
 
     // redraw just the change
     Invalidate(changeRect, PR_TRUE);
+
+    if (mScrollbarListener)
+      mScrollbarListener->PositionChanged(mCurPos, curpos);
+    
+    mCurPos = curpos;
+
 }
 
 void
@@ -527,6 +538,7 @@ nsSliderFrame::SetCurrentPosition(nsIPresContext& aPresContext, nsIContent* scro
   nscoord onePixel = NSIntPixelsToTwips(1, p2t);
 
    // get our current position and max position from our content node
+  PRInt32 curpos = GetCurrentPosition(scrollbar);
   PRInt32 maxpos = GetMaxPosition(scrollbar);
 
   // get the new position and make sure it is in bounds
@@ -541,6 +553,8 @@ nsSliderFrame::SetCurrentPosition(nsIPresContext& aPresContext, nsIContent* scro
   // set the new position
   scrollbar->SetAttribute(kNameSpaceID_None, nsXULAtoms::curpos, nsString(ch), PR_TRUE);
 
+  CurrentPositionChanged(&aPresContext);
+
   printf("Current Pos=%d\n",newpos);
   
 }
@@ -759,3 +773,10 @@ nsSliderFrame::Release(void)
 {
     return NS_OK;
 }
+
+void 
+nsSliderFrame::SetScrollbarListener(nsIScrollbarListener* aListener)
+{
+  // Don't addref/release this, since it's actually a frame.
+  mScrollbarListener = aListener;
+}

layout/xul/base/src/nsSliderFrame.h

@@ -31,6 +31,7 @@
 #include "nsIDOMMouseListener.h"
 
 class nsString;
+class nsIScrollbarListener;
 
 nsresult NS_NewSliderFrame(nsIFrame** aResult) ;
 
@@ -156,6 +157,7 @@ public:
   static PRInt32 GetIntegerAttribute(nsIContent* content, nsIAtom* atom, PRInt32 defaultValue);
   static PRInt32 IsHorizontal(nsIContent* content);
 
+  void SetScrollbarListener(nsIScrollbarListener* aListener);
 
 protected:
 
@@ -184,6 +186,10 @@ private:
   nscoord mDragStartPx;
   nscoord mThumbStart;
 
+  PRInt32 mCurPos;
+
+  nsIScrollbarListener* mScrollbarListener;
+
 }; // class nsSliderFrame
 
 #endif