Merge patch for stacked floats with shape-outside from WebKit

Source/WebCore/rendering/RenderBlockLineLayout.cpp

Index: Source/WebCore/rendering/RenderBlockLineLayout.cpp
diff --git a/Source/WebCore/rendering/RenderBlockLineLayout.cpp b/Source/WebCore/rendering/RenderBlockLineLayout.cpp
index 5ec6851eb6de76292d3c6d88c78296870563715e..181e4b1651b0f79ba5979249743eeef858b35c52 100644
--- a/Source/WebCore/rendering/RenderBlockLineLayout.cpp
+++ b/Source/WebCore/rendering/RenderBlockLineLayout.cpp
@@ -182,6 +182,25 @@ inline void LineWidth::shrinkAvailableWidthForNewFloatIfNeeded(RenderBlock::Floa
         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));
@@ -190,6 +209,8 @@ inline void LineWidth::shrinkAvailableWidthForNewFloatIfNeeded(RenderBlock::Floa
     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
@@ -200,6 +221,8 @@ inline void LineWidth::shrinkAvailableWidthForNewFloatIfNeeded(RenderBlock::Floa
     } else {
         float newRight = m_block->logicalLeftForFloat(newFloat);
 #if ENABLE(CSS_EXCLUSIONS)
+        if (lastShapeOutsideInfo)
+            newRight -= lastShapeOutsideInfo->leftSegmentShapeBoundingBoxDelta();
         if (shapeOutsideInfo)
             newRight += shapeOutsideInfo->leftSegmentShapeBoundingBoxDelta();
 #endif