Get rid of clampScrollOffset and make maximumScrollPosition sane.

This also gets rid of a bug in clampScrollOffset that sometimes caused it to use a maximum offset that was one pixel too small, so a few tests need to be rebaselined.

BUG=492871
R=skobes@chromium.org

Review URL: https://codereview.chromium.org/1223173006

git-svn-id: svn://svn.chromium.org/blink/trunk@201983 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/TestExpectations

@@ -70,6 +70,12 @@ crbug.com/463358 [ Mac Linux Debug ] fast/backgrounds/transformed-body-backgroun
 crbug.com/463358 [ Mac Linux Debug ] svg/W3C-SVG-1.1/paths-data-02-t.svg [ ImageOnlyFailure ]
 crbug.com/463358 [ Mac Linux Debug ] css3/masking/clip-path-polygon.html [ ImageOnlyFailure ]
 
+crbug.com/492871 [ Mac ] fast/forms/listbox-scrollbar-incremental-load.html [ NeedsRebaseline ]
+crbug.com/492871 [ Mac ] fast/forms/select-initial-position.html [ NeedsRebaseline ]
+crbug.com/492871 [ Mac ] fast/overflow/overflow-text-hit-testing.html [ NeedsRebaseline ]
+crbug.com/492871 [ Mac ] fast/repaint/caret-invalidation-in-overflow-scroll.html [ NeedsRebaseline ]
+crbug.com/492871 [ Win ] fast/overflow/overflow-text-hit-testing.html [ NeedsRebaseline ]
+
 crbug.com/267206 [ Mac ] virtual/rootlayerscrolls/fast/scrolling/scrollbar-tickmarks-hittest.html [ Timeout ]
 
 # Times out on the windows trybot.

third_party/WebKit/Source/core/frame/FrameView.cpp

@@ -2990,17 +2990,10 @@ IntPoint FrameView::maximumScrollPosition() const
 {
     // Make the same calculation as in CC's LayerImpl::MaxScrollOffset()
     // FIXME: We probably shouldn't be storing the bounds in a float. crbug.com/422331.
-    FloatSize visibleSize = visibleContentSize(ExcludeScrollbars);
-    visibleSize.expand(0, m_topControlsViewportAdjustment);
-
-    FloatSize contentBounds = contentsSize();
-    contentBounds = flooredIntSize(contentBounds);
-
-    FloatSize maximumOffset = contentBounds - visibleSize - toIntSize(scrollOrigin());
-
-    IntPoint snappedMaximumOffset = flooredIntPoint(maximumOffset);
-    snappedMaximumOffset = snappedMaximumOffset.expandedTo(minimumScrollPosition());
-    return snappedMaximumOffset;
+    IntSize visibleSize = visibleContentSize(ExcludeScrollbars) + topControlsSize();
+    IntSize contentBounds = contentsSize();
+    IntPoint maximumPosition = -scrollOrigin() + (contentBounds - visibleSize);
+    return maximumPosition.expandedTo(minimumScrollPosition());
 }
 
 void FrameView::addChild(PassRefPtrWillBeRawPtr<Widget> prpChild)

third_party/WebKit/Source/core/frame/FrameView.h

@@ -336,6 +336,7 @@ public:
     // commit scroll offsets before a WebView::resize occurs, we need to adjust
     // our scroll extents to prevent clamping the scroll offsets.
     void setTopControlsViewportAdjustment(float);
+    IntSize topControlsSize() const { return IntSize(0, roundf(m_topControlsViewportAdjustment)); }
 
     IntPoint maximumScrollPosition() const override;
 

third_party/WebKit/Source/core/layout/LayoutTextControlSingleLine.cpp

@@ -398,10 +398,7 @@ LayoutUnit LayoutTextControlSingleLine::scrollWidth() const
         // Adjust scrollWidth to inculde input element horizontal paddings and
         // decoration width
         LayoutUnit adjustment = clientWidth() - inner->clientWidth();
-        // TODO(leviw): We floor to avoid breaking JS that tries to scroll to
-        // scrollWidth - clientWidth.
-        // TODO(leviw): These values are broken when zooming. crbug.com/471412
-        return inner->scrollWidth().floor() + adjustment;
+        return inner->scrollWidth() + adjustment;
     }
     return LayoutBlockFlow::scrollWidth();
 }
@@ -412,10 +409,7 @@ LayoutUnit LayoutTextControlSingleLine::scrollHeight() const
         // Adjust scrollHeight to include input element vertical paddings and
         // decoration height
         LayoutUnit adjustment = clientHeight() - inner->clientHeight();
-        // TODO(leviw): We floor to avoid breaking JS that tries to scroll to
-        // scrollHeight - clientHeight.
-        // TODO(leviw): These values are broken when zooming. crbug.com/471412
-        return inner->scrollHeight().floor() + adjustment;
+        return inner->scrollHeight() + adjustment;
     }
     return LayoutBlockFlow::scrollHeight();
 }

third_party/WebKit/Source/core/paint/DeprecatedPaintLayerScrollableArea.cpp

@@ -489,9 +489,17 @@ IntPoint DeprecatedPaintLayerScrollableArea::minimumScrollPosition() const
 
 IntPoint DeprecatedPaintLayerScrollableArea::maximumScrollPosition() const
 {
-    if (!box().hasOverflowClip())
-        return -scrollOrigin();
-    return -scrollOrigin() + IntPoint(pixelSnappedScrollWidth(), pixelSnappedScrollHeight()) - enclosingIntRect(box().clientBoxRect()).size();
+    IntSize contentSize;
+    IntSize visibleSize;
+    if (layer()->isRootLayer()) {
+        FrameView* frameView = box().frameView();
+        contentSize = frameView->contentsSize();
+        visibleSize = frameView->visibleContentSize(ExcludeScrollbars) + frameView->topControlsSize();
+    } else if (box().hasOverflowClip()) {
+        contentSize = IntSize(pixelSnappedScrollWidth(), pixelSnappedScrollHeight());
+        visibleSize = enclosingIntRect(box().clientBoxRect()).size();
+    }
+    return -scrollOrigin() + (contentSize - visibleSize);
 }
 
 IntRect DeprecatedPaintLayerScrollableArea::visibleContentRect(IncludeScrollbarsInRect scrollbarInclusion) const
@@ -642,14 +650,13 @@ void DeprecatedPaintLayerScrollableArea::computeScrollDimensions()
     setScrollOrigin(IntPoint(-scrollableLeftOverflow, -scrollableTopOverflow));
 }
 
-void DeprecatedPaintLayerScrollableArea::scrollToOffset(const DoubleSize& scrollOffset, ScrollOffsetClamping clamp, ScrollBehavior scrollBehavior)
+void DeprecatedPaintLayerScrollableArea::scrollToPosition(const DoublePoint& scrollPosition, ScrollOffsetClamping clamp, ScrollBehavior scrollBehavior)
 {
     cancelProgrammaticScrollAnimation();
-    DoubleSize newScrollOffset = clamp == ScrollOffsetClamped ? clampScrollOffset(scrollOffset) : scrollOffset;
-    if (newScrollOffset != adjustedScrollOffset()) {
-        DoublePoint origin(scrollOrigin());
-        ScrollableArea::setScrollPosition(-origin + newScrollOffset, ProgrammaticScroll, scrollBehavior);
-    }
+
+    DoublePoint newScrollPosition = clamp == ScrollOffsetClamped ? clampScrollPosition(scrollPosition) : scrollPosition;
+    if (newScrollPosition != scrollPositionDouble())
+        ScrollableArea::setScrollPosition(newScrollPosition, ProgrammaticScroll, scrollBehavior);
 }
 
 void DeprecatedPaintLayerScrollableArea::updateScrollDimensions(DoubleSize& scrollOffset, bool& autoHorizontalScrollBarChanged, bool& autoVerticalScrollBarChanged)
@@ -691,9 +698,9 @@ void DeprecatedPaintLayerScrollableArea::finalizeScrollDimensions(const DoubleSi
 
     // Layout may cause us to be at an invalid scroll position. In this case we need
     // to pull our scroll offsets back to the max (or push them up to the min).
-    DoubleSize clampedScrollOffset = clampScrollOffset(adjustedScrollOffset());
-    if (clampedScrollOffset != adjustedScrollOffset())
-        scrollToOffset(clampedScrollOffset);
+    DoublePoint clampedScrollPosition = clampScrollPosition(scrollPositionDouble());
+    if (clampedScrollPosition != scrollPositionDouble())
+        scrollToPosition(clampedScrollPosition);
 
     if (originalScrollOffset != adjustedScrollOffset()) {
         DoublePoint origin(scrollOrigin());
@@ -903,16 +910,6 @@ void DeprecatedPaintLayerScrollableArea::updateAfterOverflowRecalc()
         box().setNeedsLayoutAndFullPaintInvalidation(LayoutInvalidationReason::Unknown);
 }
 
-DoubleSize DeprecatedPaintLayerScrollableArea::clampScrollOffset(const DoubleSize& scrollOffset) const
-{
-    int maxX = scrollWidth() - box().pixelSnappedClientWidth();
-    int maxY = scrollHeight() - box().pixelSnappedClientHeight();
-
-    double x = std::max(std::min(scrollOffset.width(), static_cast<double>(maxX)), 0.0);
-    double y = std::max(std::min(scrollOffset.height(), static_cast<double>(maxY)), 0.0);
-    return DoubleSize(x, y);
-}
-
 IntRect DeprecatedPaintLayerScrollableArea::rectForHorizontalScrollbar(const IntRect& borderBoxRect) const
 {
     if (!m_hBar)
@@ -1402,12 +1399,12 @@ LayoutRect DeprecatedPaintLayerScrollableArea::scrollIntoView(const LayoutRect&
     LayoutRect layerBounds(0, 0, box().clientWidth(), box().clientHeight());
     LayoutRect r = ScrollAlignment::getRectToExpose(layerBounds, localExposeRect, alignX, alignY);
 
-    DoubleSize clampedScrollOffset = clampScrollOffset(adjustedScrollOffset() + roundedIntSize(r.location()));
-    if (clampedScrollOffset == adjustedScrollOffset())
+    DoublePoint clampedScrollPosition = clampScrollPosition(scrollPositionDouble() + roundedIntSize(r.location()));
+    if (clampedScrollPosition == scrollPositionDouble())
         return rect;
 
     DoubleSize oldScrollOffset = adjustedScrollOffset();
-    scrollToOffset(clampedScrollOffset);
+    scrollToPosition(clampedScrollPosition);
     DoubleSize scrollOffsetDifference = adjustedScrollOffset() - oldScrollOffset;
     localExposeRect.move(-LayoutSize(scrollOffsetDifference));
     return LayoutRect(box().localToAbsoluteQuad(FloatQuad(FloatRect(localExposeRect)), UseTransforms).boundingBox());

third_party/WebKit/Source/core/paint/DeprecatedPaintLayerScrollableArea.h

@@ -132,7 +132,12 @@ public:
     // FIXME: We shouldn't allow access to m_overflowRect outside this class.
     LayoutRect overflowRect() const { return m_overflowRect; }
 
-    void scrollToOffset(const DoubleSize& scrollOffset, ScrollOffsetClamping = ScrollOffsetUnclamped, ScrollBehavior = ScrollBehaviorInstant);
+    void scrollToPosition(const DoublePoint& scrollPosition, ScrollOffsetClamping = ScrollOffsetUnclamped, ScrollBehavior = ScrollBehaviorInstant);
+
+    void scrollToOffset(const DoubleSize& scrollOffset, ScrollOffsetClamping clamp = ScrollOffsetUnclamped, ScrollBehavior scrollBehavior = ScrollBehaviorInstant)
+    {
+        scrollToPosition(-scrollOrigin() + scrollOffset, clamp, scrollBehavior);
+    }
 
     void scrollToXOffset(double x, ScrollOffsetClamping clamp = ScrollOffsetUnclamped, ScrollBehavior scrollBehavior = ScrollBehaviorInstant)
     {
@@ -243,10 +248,6 @@ private:
 
     void computeScrollDimensions();
 
-    // TODO(bokan): This method hides the base class version and is subtly different.
-    // Should be unified.
-    DoubleSize clampScrollOffset(const DoubleSize&) const;
-
     void setScrollOffset(const IntPoint&, ScrollType) override;
     void setScrollOffset(const DoublePoint&, ScrollType) override;