1 files changed, 24 insertions, 10 deletions

diff --git a/WebCore/platform/ScrollView.h b/WebCore/platform/ScrollView.h
index 3627283..6f7ec8b 100644
--- a/WebCore/platform/ScrollView.h
+++ b/WebCore/platform/ScrollView.h
@@ -168,7 +168,7 @@ public:
     IntSize scrollOffset() const { return visibleContentRect().location() - IntPoint(); } // Gets the scrolled position as an IntSize. Convenient for adding to other sizes.
     IntPoint maximumScrollPosition() const; // The maximum position we can be scrolled to.
     IntPoint minimumScrollPosition() const; // The minimum position we can be scrolled to.
-    // Adjust the pass in scroll position within the minimum and maximum positions.
+    // Adjust the passed in scroll position to keep it between the minimum and maximum positions.
     IntPoint adjustScrollPositionWithinRange(const IntPoint&) const; 
     int scrollX() const { return scrollPosition().x(); }
     int scrollY() const { return scrollPosition().y(); }
@@ -179,7 +179,10 @@ public:
 
     // This function scrolls by lines, pages or pixels.
     bool scroll(ScrollDirection, ScrollGranularity);
-        
+    
+    // A logical scroll that just ends up calling the corresponding physical scroll() based off the document's writing mode.
+    bool logicalScroll(ScrollLogicalDirection, ScrollGranularity);
+
     // Scroll the actual contents of the view (either blitting or invalidating as needed).
     void scrollContents(const IntSize& scrollDelta);
 
@@ -289,9 +292,12 @@ protected:
     // Scroll the content by invalidating everything.
     virtual void scrollContentsSlowPath(const IntRect& updateRect);
 
-    void setScrollOriginX(int);
-    int scrollOriginX() { return m_scrollOriginX; }
-    void updateScrollbars();
+    void setScrollOrigin(const IntPoint&, bool updatePosition);
+    IntPoint scrollOrigin() { return m_scrollOrigin; }
+
+    // Subclassed by FrameView to check the writing-mode of the document.
+    virtual bool isVerticalDocument() const { return true; }
+    virtual bool isFlippedDocument() const { return false; }
 
 private:
     RefPtr<Scrollbar> m_horizontalScrollbar;
@@ -328,10 +334,18 @@ private:
     bool m_paintsEntireContents;
     bool m_delegatesScrolling;
 
-    // m_scrollOriginX is 0 for LTR page. And it is negative of left layout
-    // overflow for RTL page. It is mainly used to set the horizontal scrollbar
-    // position for RTL page.
-    int m_scrollOriginX;
+    // There are 8 possible combinations of writing mode and direction.  Scroll origin will be non-zero in the x or y axis
+    // if there is any reversed direction or writing-mode.  The combinations are:
+    // writing-mode / direction     scrollOrigin.x() set    scrollOrigin.y() set
+    // horizontal-tb / ltr          NO                      NO
+    // horizontal-tb / rtl          YES                     NO
+    // horizontal-bt / ltr          NO                      YES
+    // horizontal-bt / rtl          YES                     YES
+    // vertical-lr / ltr            NO                      NO
+    // vertical-lr / rtl            NO                      YES
+    // vertical-rl / ltr            YES                     NO
+    // vertical-rl / rtl            YES                     YES
+    IntPoint m_scrollOrigin;
 
     void init();
     void destroy();
@@ -361,7 +375,7 @@ private:
     void platformRepaintContentRectangle(const IntRect&, bool now);
     bool platformIsOffscreen() const;
    
-    void platformSetScrollOriginX(int);
+    void platformSetScrollOrigin(const IntPoint&, bool updatePosition);
 
 #if PLATFORM(ANDROID)
     int platformActualWidth() const;