Revert of Calculate paint invalidation rect for scrollbars

third_party/WebKit/Source/platform/scroll/ScrollableArea.h

Index: third_party/WebKit/Source/platform/scroll/ScrollableArea.h
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollableArea.h b/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
index bc261b77f4d9b0381eccf2bf36d5478dd6b6bae6..26b8fb97111dd14c8030be7744b14c9a21c29066 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
+++ b/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
@@ -147,10 +147,10 @@
 
     virtual bool isActive() const = 0;
     virtual int scrollSize(ScrollbarOrientation) const = 0;
-    void setScrollbarNeedsPaintInvalidation(Scrollbar*);
+    virtual void invalidateScrollbar(Scrollbar*, const IntRect&);
     virtual bool isScrollCornerVisible() const = 0;
     virtual IntRect scrollCornerRect() const = 0;
-    void setScrollCornerNeedsPaintInvalidation();
+    virtual void invalidateScrollCorner(const IntRect&);
     virtual void getTickmarks(Vector<IntRect>&) const { }
 
     // Convert points and rects between the scrollbar and its containing view.
@@ -235,6 +235,25 @@
     int maximumScrollPosition(ScrollbarOrientation orientation) { return orientation == HorizontalScrollbar ? maximumScrollPosition().x() : maximumScrollPosition().y(); }
     int clampScrollPosition(ScrollbarOrientation orientation, int pos)  { return std::max(std::min(pos, maximumScrollPosition(orientation)), minimumScrollPosition(orientation)); }
 
+    bool hasVerticalBarDamage() const { return !m_verticalBarDamage.isEmpty(); }
+    bool hasHorizontalBarDamage() const { return !m_horizontalBarDamage.isEmpty(); }
+    const IntRect& verticalBarDamage() const { return m_verticalBarDamage; }
+    const IntRect& horizontalBarDamage() const { return m_horizontalBarDamage; }
+
+    void addScrollbarDamage(Scrollbar* scrollbar, const IntRect& rect)
+    {
+        if (scrollbar == horizontalScrollbar())
+            m_horizontalBarDamage.unite(rect);
+        else
+            m_verticalBarDamage.unite(rect);
+    }
+
+    void resetScrollbarDamage()
+    {
+        m_verticalBarDamage = IntRect();
+        m_horizontalBarDamage = IntRect();
+    }
+
     virtual GraphicsLayer* layerForContainer() const;
     virtual GraphicsLayer* layerForScrolling() const { return 0; }
     virtual GraphicsLayer* layerForHorizontalScrollbar() const { return 0; }
@@ -251,8 +270,8 @@
 
     virtual ~ScrollableArea();
 
-    // Called when any of horizontal scrollbar, vertical scrollbar and scroll corner is setNeedsPaintInvalidation.
-    virtual void scrollControlWasSetNeedsPaintInvalidation() = 0;
+    virtual void invalidateScrollbarRect(Scrollbar*, const IntRect&) = 0;
+    virtual void invalidateScrollCornerRect(const IntRect&) = 0;
 
     // Returns the default scroll style this area should scroll with when not
     // explicitly specified. E.g. The scrolling behavior of an element can be
@@ -292,16 +311,6 @@
     void scrollPositionChanged(const DoublePoint&, ScrollType);
 
     void clearScrollAnimators();
-
-    bool horizontalScrollbarNeedsPaintInvalidation() const { return m_horizontalScrollbarNeedsPaintInvalidation; }
-    bool verticalScrollbarNeedsPaintInvalidation() const { return m_verticalScrollbarNeedsPaintInvalidation; }
-    bool scrollCornerNeedsPaintInvalidation() const { return m_scrollCornerNeedsPaintInvalidation; }
-    void clearNeedsPaintInvalidationForScrollControls()
-    {
-        m_horizontalScrollbarNeedsPaintInvalidation = false;
-        m_verticalScrollbarNeedsPaintInvalidation = false;
-        m_scrollCornerNeedsPaintInvalidation = false;
-    }
 
 private:
     void programmaticScrollHelper(const DoublePoint&, ScrollBehavior);
@@ -325,6 +334,10 @@
     virtual int documentStep(ScrollbarOrientation) const;
     virtual float pixelStep(ScrollbarOrientation) const;
 
+    // Stores the paint invalidations for the scrollbars during layout.
+    IntRect m_horizontalBarDamage;
+    IntRect m_verticalBarDamage;
+
     struct ScrollableAreaAnimators {
         OwnPtr<ScrollAnimatorBase> scrollAnimator;
         OwnPtr<ProgrammaticScrollAnimator> programmaticScrollAnimator;
@@ -337,10 +350,6 @@
     unsigned m_scrollbarOverlayStyle : 2; // ScrollbarOverlayStyle
 
     unsigned m_scrollOriginChanged : 1;
-
-    unsigned m_horizontalScrollbarNeedsPaintInvalidation : 1;
-    unsigned m_verticalScrollbarNeedsPaintInvalidation : 1;
-    unsigned m_scrollCornerNeedsPaintInvalidation : 1;
 
     // 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: