Refactor ScrollableArea::setScrollPosition.

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

 /*
  * Copyright (c) 2010, Google Inc. All rights reserved.
  * Copyright (C) 2008, 2011 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 160 matching lines @@
   FloatSize unscrollableAxisDelta = pixelDelta - scrollableAxisDelta;
   result.unusedScrollDeltaX += unscrollableAxisDelta.width();
   result.unusedScrollDeltaY += unscrollableAxisDelta.height();
 
   return result;
 }
 
 void ScrollableArea::setScrollPosition(const DoublePoint& position,
                                        ScrollType scrollType,
                                        ScrollBehavior behavior) {
+  DoublePoint clampedPosition = clampScrollPosition(position);
+  if (shouldUseIntegerScrollOffset())
+    clampedPosition = flooredIntPoint(clampedPosition);
+  if (clampedPosition == scrollPositionDouble())
+    return;
+
   if (behavior == ScrollBehaviorAuto)
     behavior = scrollBehaviorStyle();
 
   switch (scrollType) {
     case CompositorScroll:
-      scrollPositionChanged(clampScrollPosition(position), scrollType);
+      scrollPositionChanged(clampedPosition, scrollType);
       break;
     case AnchoringScroll:
-      scrollAnimator().adjustAnimationAndSetScrollPosition(position,
+      scrollAnimator().adjustAnimationAndSetScrollPosition(clampedPosition,

[bokan, 2016/10/01 20:32:47]

I think you can remove the clamps in
ScrollAnimator::adjustAnimationAndSetScrollPosition and
ScrollAnimatorCompositorCoordinator::adjustAnimationAndSetScrollPosition.

[szager1, 2016/10/02 19:35:28]

Done.

                                                            scrollType);
       break;
     case ProgrammaticScroll:
-      programmaticScrollHelper(position, behavior);
+      programmaticScrollHelper(clampedPosition, behavior);
       break;
     case UserScroll:
-      userScrollHelper(position, behavior);
+      userScrollHelper(clampedPosition, behavior);
       break;
     default:
       ASSERT_NOT_REACHED();
   }
 }
 
 void ScrollableArea::scrollBy(const DoubleSize& delta,
                               ScrollType type,
                               ScrollBehavior behavior) {
   setScrollPosition(scrollPositionDouble() + delta, type, behavior);
@@ skipping 57 matching lines @@
 
 void ScrollableArea::scrollPositionChanged(const DoublePoint& position,
                                            ScrollType scrollType) {
   TRACE_EVENT0("blink", "ScrollableArea::scrollPositionChanged");
 
   DoublePoint oldPosition = scrollPositionDouble();
   DoublePoint truncatedPosition =
       shouldUseIntegerScrollOffset() ? flooredIntPoint(position) : position;
 
   // Tell the derived class to scroll its contents.
-  setScrollOffset(truncatedPosition, scrollType);
+  updateScrollPosition(truncatedPosition, scrollType);
 
   // Tell the scrollbars to update their thumb postions.
   // If the scrollbar does not have its own layer, it must always be
   // invalidated to reflect the new thumb position, even if the theme did not
   // invalidate any individual part.
   if (Scrollbar* horizontalScrollbar = this->horizontalScrollbar())
     horizontalScrollbar->offsetDidChange();
   if (Scrollbar* verticalScrollbar = this->verticalScrollbar())
     verticalScrollbar->offsetDidChange();
 
@@ skipping 14 matching lines @@
     behavior = ScrollBehaviorInstant;
   else if (behaviorString == "smooth")
     behavior = ScrollBehaviorSmooth;
   else
     return false;
 
   return true;
 }
 
 // NOTE: Only called from Internals for testing.
-void ScrollableArea::setScrollOffsetFromInternals(const IntPoint& offset) {
-  scrollPositionChanged(DoublePoint(offset), ProgrammaticScroll);
+void ScrollableArea::updateScrollPositionFromInternals(
+    const IntPoint& position) {
+  scrollPositionChanged(DoublePoint(position), ProgrammaticScroll);
 }
 
 void ScrollableArea::contentAreaWillPaint() const {
   if (ScrollAnimatorBase* scrollAnimator = existingScrollAnimator())
     scrollAnimator->contentAreaWillPaint();
 }
 
 void ScrollableArea::mouseEnteredContentArea() const {
   if (ScrollAnimatorBase* scrollAnimator = existingScrollAnimator())
     scrollAnimator->mouseEnteredContentArea();
@@ skipping 273 matching lines @@
   return IntSize(std::max(0, size.width() - verticalScrollbarWidth()),
                  std::max(0, size.height() - horizontalScrollbarHeight()));
 }
 
 DEFINE_TRACE(ScrollableArea) {
   visitor->trace(m_scrollAnimator);
   visitor->trace(m_programmaticScrollAnimator);
 }
 
 }  // namespace blink