Add overflow:auto scrollbars to child flex basis.

Source/core/layout/LayoutBlock.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 90 matching lines @@
 static TrackedDescendantsMap* gPositionedDescendantsMap = nullptr;
 
 // This map keeps track of the descendants whose 'height' is percentage associated
 // with a containing block. Like |gPositionedDescendantsMap|, it is also recomputed
 // for every layout (see the comment above about why).
 static TrackedDescendantsMap* gPercentHeightDescendantsMap = nullptr;
 
 static TrackedContainerMap* gPositionedContainerMap = nullptr;
 static TrackedContainerMap* gPercentHeightContainerMap = nullptr;
 
-typedef WTF::HashSet<LayoutBlock*> DelayedUpdateScrollInfoSet;
+struct ScrollInfo {
+    DoubleSize scrollOffset;
+    bool autoHorizontalScrollBarChanged;
+    bool autoVerticalScrollBarChanged;
+    bool hasOffset() const { return scrollOffset != DoubleSize(); }
+    bool scrollBarsChanged() const { return autoHorizontalScrollBarChanged || autoVerticalScrollBarChanged; }
+    void merge(const ScrollInfo& other)
+    {
+        // We always keep the first scrollOffset we saw for this block, so don't copy that field.
+        autoHorizontalScrollBarChanged |= other.autoHorizontalScrollBarChanged;
+        autoVerticalScrollBarChanged |= other.autoVerticalScrollBarChanged;
+    }
+};
+typedef WTF::HashMap<LayoutBlock*, ScrollInfo> DelayedUpdateScrollInfoMap;
 static int gDelayUpdateScrollInfo = 0;
-static DelayedUpdateScrollInfoSet* gDelayedUpdateScrollInfoSet = nullptr;
+static DelayedUpdateScrollInfoMap* gDelayedUpdateScrollInfoMap = nullptr;
 
 LayoutBlock::LayoutBlock(ContainerNode* node)
     : LayoutBox(node)
     , m_hasMarginBeforeQuirk(false)
     , m_hasMarginAfterQuirk(false)
     , m_beingDestroyed(false)
     , m_hasMarkupTruncation(false)
     , m_widthAvailableToChildrenChanged(false)
     , m_hasOnlySelfCollapsingChildren(false)
     , m_descendantsWithFloatsMarkedForLayout(false)
@@ skipping 101 matching lines @@
                         childBox->remove();
                 }
             }
         } else if (parent()) {
             parent()->dirtyLinesFromChangedChild(this);
         }
     }
 
     m_lineBoxes.deleteLineBoxes();
 
-    if (UNLIKELY(gDelayedUpdateScrollInfoSet != 0))
-        gDelayedUpdateScrollInfoSet->remove(this);
+    if (UNLIKELY(gDelayedUpdateScrollInfoMap != 0))
+        gDelayedUpdateScrollInfoMap->remove(this);
 
     if (TextAutosizer* textAutosizer = document().textAutosizer())
         textAutosizer->destroy(this);
 
     LayoutBox::willBeDestroyed();
 }
 
 void LayoutBlock::styleWillChange(StyleDifference diff, const ComputedStyle& newStyle)
 {
     const ComputedStyle* oldStyle = style();
@@ skipping 574 matching lines @@
                 return false;
         }
         return true;
     }
     return false;
 }
 
 void LayoutBlock::startDelayUpdateScrollInfo()
 {
     if (gDelayUpdateScrollInfo == 0) {
-        ASSERT(!gDelayedUpdateScrollInfoSet);
-        gDelayedUpdateScrollInfoSet = new DelayedUpdateScrollInfoSet;
+        ASSERT(!gDelayedUpdateScrollInfoMap);
+        gDelayedUpdateScrollInfoMap = new DelayedUpdateScrollInfoMap;
     }
-    ASSERT(gDelayedUpdateScrollInfoSet);
+    ASSERT(gDelayedUpdateScrollInfoMap);
     ++gDelayUpdateScrollInfo;
 }
 
 void LayoutBlock::finishDelayUpdateScrollInfo()
 {
     --gDelayUpdateScrollInfo;
     ASSERT(gDelayUpdateScrollInfo >= 0);
     if (gDelayUpdateScrollInfo == 0) {
-        ASSERT(gDelayedUpdateScrollInfoSet);
+        ASSERT(gDelayedUpdateScrollInfoMap);
 
-        OwnPtr<DelayedUpdateScrollInfoSet> infoSet(adoptPtr(gDelayedUpdateScrollInfoSet));
-        gDelayedUpdateScrollInfoSet = nullptr;
+        OwnPtr<DelayedUpdateScrollInfoMap> infoMap(adoptPtr(gDelayedUpdateScrollInfoMap));
+        gDelayedUpdateScrollInfoMap = nullptr;
 
-        for (auto* block : *infoSet) {
-            if (block->hasOverflowClip()) {
-                block->layer()->scrollableArea()->updateAfterLayout();
+        for (auto block : *infoMap) {
+            if (block.key->hasOverflowClip()) {
+                DeprecatedPaintLayerScrollableArea* scrollableArea = block.key->layer()->scrollableArea();
+                ScrollInfo& scrollInfo = block.value;
+                scrollableArea->finalizeScrollDimensions(scrollInfo.scrollOffset, scrollInfo.autoHorizontalScrollBarChanged, scrollInfo.autoVerticalScrollBarChanged);
             }
         }
     }
 }
 
 void LayoutBlock::updateScrollInfoAfterLayout()
 {
     if (hasOverflowClip()) {
         if (style()->isFlippedBlocksWritingMode()) {
             // FIXME: https://bugs.webkit.org/show_bug.cgi?id=97937
             // Workaround for now. We cannot delay the scroll info for overflow
             // for items with opposite writing directions, as the contents needs
             // to overflow in that direction
             layer()->scrollableArea()->updateAfterLayout();
             return;
         }
 
-        if (gDelayUpdateScrollInfo)
-            gDelayedUpdateScrollInfoSet->add(this);
-        else
+        if (gDelayUpdateScrollInfo) {
+            LayoutUnit logicalWidthExcludingScrollbar = logicalWidth() - scrollbarLogicalWidth();
+            LayoutUnit logicalHeightExcludingScrollbar = logicalHeight() - scrollbarLogicalHeight();
+            ScrollInfo scrollInfo;
+            layer()->scrollableArea()->updateScrollDimensions(scrollInfo.scrollOffset, scrollInfo.autoHorizontalScrollBarChanged, scrollInfo.autoVerticalScrollBarChanged);
+            DelayedUpdateScrollInfoMap::AddResult scrollInfoIterator = gDelayedUpdateScrollInfoMap->add(this, scrollInfo);
+            if (!scrollInfoIterator.isNewEntry)
+                scrollInfoIterator.storedValue->value.merge(scrollInfo);
+            if (scrollInfo.autoHorizontalScrollBarChanged)
+                setLogicalHeight(logicalHeightExcludingScrollbar + scrollbarLogicalHeight());
+            if (scrollInfo.autoVerticalScrollBarChanged)
+                setLogicalWidth(logicalWidthExcludingScrollbar + scrollbarLogicalWidth());

[cbiesinger, 2015/11/18 18:41:35]

I thought more about this block and I am no longer sure that it is correct, at
least for the width. It also looks like we didn't use to do this, right?

Rationale: There's actually very few cases where the appearance/disappearance of
the scrollbar should change the logicalWidth(). Not for an explicit width
(because, it seems, the scrollbar is part of the content box), and not for
width:auto either because either way that one is fill-available.

Thoughts?

+        } else {
             layer()->scrollableArea()->updateAfterLayout();
+        }
     }
 }
 
 void LayoutBlock::layout()
 {
     LayoutAnalyzer::Scope analyzer(*this);
 
     // Table cells call layoutBlock directly, so don't add any logic here.  Put code into
     // layoutBlock().
     layoutBlock(false);
@@ skipping 2000 matching lines @@
 void LayoutBlock::showLineTreeAndMark(const InlineBox* markedBox1, const char* markedLabel1, const InlineBox* markedBox2, const char* markedLabel2, const LayoutObject* obj) const
 {
     showLayoutObject();
     for (const RootInlineBox* root = firstRootBox(); root; root = root->nextRootBox())
         root->showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, 1);
 }
 
 #endif
 
 } // namespace blink