Merge patch for stacked floats with shape-outside from WebKit

Source/WebCore/rendering/RenderBlockLineLayout.cpp

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All right reserved.
  * Copyright (C) 2010 Google Inc. 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
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 164 matching lines @@
     computeAvailableWidthFromLeftAndRight();
 }
 
 inline void LineWidth::shrinkAvailableWidthForNewFloatIfNeeded(RenderBlock::FloatingObject* newFloat)
 {
     LayoutUnit height = m_block->logicalHeight();
     if (height < m_block->logicalTopForFloat(newFloat) || height >= m_block->logicalBottomForFloat(newFloat))
         return;
 
 #if ENABLE(CSS_EXCLUSIONS)
+    // When floats with shape outside are stacked, the floats are positioned based on the bounding box of the shape,
+    // not the shape's contour. Since we computed the width based on the shape contour when we added the float,
+    // when we add a subsequent float on the same line, we need to undo the shape delta in order to position
+    // based on the bounding box. In order to do this, we need to walk back through the floating object list to find
+    // the first previous float that is on the same side as our newFloat.
+    ExclusionShapeOutsideInfo* lastShapeOutsideInfo = 0;
+    const RenderBlock::FloatingObjectSet& floatingObjectSet = m_block->m_floatingObjects->set();
+    RenderBlock::FloatingObjectSetIterator it = floatingObjectSet.end();
+    RenderBlock::FloatingObjectSetIterator begin = floatingObjectSet.begin();
+    for (--it; it != begin; --it) {

[Julien - ping for review, 2013/04/10 21:33:59]

Won't this loop ignore the first float if it is your "last float"? (I don't
really like the name as it's imprecise and fairly confusing).

You will also never got into the for loop if you have only one float.

+        RenderBlock::FloatingObject* lastFloat = *it;
+        if (lastFloat != newFloat && lastFloat->type() == newFloat->type()) {
+            lastShapeOutsideInfo = lastFloat->renderer()->exclusionShapeOutsideInfo();
+            if (lastShapeOutsideInfo)
+                lastShapeOutsideInfo->computeSegmentsForLine(m_block->logicalHeight() - m_block->logicalTopForFloat(lastFloat) + lastShapeOutsideInfo->shapeLogicalTop(), logicalHeightForLine(m_block, m_isFirstLine));
+            break;
+        }
+    }
+
     ExclusionShapeOutsideInfo* shapeOutsideInfo = newFloat->renderer()->exclusionShapeOutsideInfo();
     if (shapeOutsideInfo)
         shapeOutsideInfo->computeSegmentsForLine(m_block->logicalHeight() - m_block->logicalTopForFloat(newFloat) + shapeOutsideInfo->shapeLogicalTop(), logicalHeightForLine(m_block, m_isFirstLine));
 #endif
 
     if (newFloat->type() == RenderBlock::FloatingObject::FloatLeft) {
         float newLeft = m_block->logicalRightForFloat(newFloat);
 #if ENABLE(CSS_EXCLUSIONS)
+        if (lastShapeOutsideInfo)
+            newLeft -= lastShapeOutsideInfo->rightSegmentShapeBoundingBoxDelta();
         if (shapeOutsideInfo)
             newLeft += shapeOutsideInfo->rightSegmentShapeBoundingBoxDelta();
 #endif
 
         if (shouldIndentText() && m_block->style()->isLeftToRightDirection())
             newLeft += floorToInt(m_block->textIndentOffset());
         m_left = max<float>(m_left, newLeft);
     } else {
         float newRight = m_block->logicalLeftForFloat(newFloat);
 #if ENABLE(CSS_EXCLUSIONS)
+        if (lastShapeOutsideInfo)
+            newRight -= lastShapeOutsideInfo->leftSegmentShapeBoundingBoxDelta();
         if (shapeOutsideInfo)
             newRight += shapeOutsideInfo->leftSegmentShapeBoundingBoxDelta();
 #endif
 
         if (shouldIndentText() && !m_block->style()->isLeftToRightDirection())
             newRight -= floorToInt(m_block->textIndentOffset());
         m_right = min<float>(m_right, newRight);
     }
 
     computeAvailableWidthFromLeftAndRight();
@@ skipping 3204 matching lines @@
     lineGridBox->alignBoxesInBlockDirection(logicalHeight(), textBoxDataMap, verticalPositionCache);
     
     setLineGridBox(lineGridBox);
     
     // FIXME: If any of the characteristics of the box change compared to the old one, then we need to do a deep dirtying
     // (similar to what happens when the page height changes). Ideally, though, we only do this if someone is actually snapping
     // to this grid.
 }
 
 }