Refactor how we handle BRs with clearance

Source/core/layout/LayoutBlockFlowLine.cpp

Index: Source/core/layout/LayoutBlockFlowLine.cpp
diff --git a/Source/core/layout/LayoutBlockFlowLine.cpp b/Source/core/layout/LayoutBlockFlowLine.cpp
index aaab3896c92b106cd938bbde5e9640730b34fbd8..f2d06dbe79a8b2c7c8e706232eabe74b5c562cbc 100644
--- a/Source/core/layout/LayoutBlockFlowLine.cpp
+++ b/Source/core/layout/LayoutBlockFlowLine.cpp
@@ -1535,9 +1535,6 @@ void LayoutBlockFlow::layoutInlineChildren(bool relayoutChildren, LayoutUnit& pa
             if (!layoutState.hasInlineChild() && o->isInline())
                 layoutState.setHasInlineChild(true);
 
-            if (o->isBR() && o->style()->clear() != CNONE)
-                layoutState.setContainsBRWithClear(true);
-
             if (o->isReplaced() || o->isFloating() || o->isOutOfFlowPositioned()) {
                 LayoutBox* box = toLayoutBox(o);
 
@@ -1655,11 +1652,8 @@ RootInlineBox* LayoutBlockFlow::determineStartPosition(LineLayoutState& layoutSt
             }
 
             // If the linebox breaks cleanly and with clearance then dirty from at least this point onwards so that we can clear the correct floats without difficulty.
-            if (!firstLineBoxWithBreakAndClearance && curr->endsWithBreak()) {
-                InlineBox* lastBox = style()->isLeftToRightDirection() ? curr->lastLeafChild() : curr->firstLeafChild();
-                if (lastBox && lastBox->layoutObject().isBR() && lastBox->layoutObject().style()->clear() != CNONE)
-                    firstLineBoxWithBreakAndClearance = curr;
-            }
+            if (!firstLineBoxWithBreakAndClearance && lineBoxHasBRWithClearance(curr))
+                firstLineBoxWithBreakAndClearance = curr;
 
             // If a new float has been inserted before this line or before its last known float, just do a full layout.
             bool encounteredNewFloat = false;
@@ -1751,6 +1745,16 @@ RootInlineBox* LayoutBlockFlow::determineStartPosition(LineLayoutState& layoutSt
     return curr;
 }
 
+
+bool LayoutBlockFlow::lineBoxHasBRWithClearance(RootInlineBox* curr)
+{
+    // If the linebox breaks cleanly and with clearance then dirty from at least this point onwards so that we can clear the correct floats without difficulty.
+    if (!curr->endsWithBreak())
+        return false;
+    InlineBox* lastBox = style()->isLeftToRightDirection() ? curr->lastLeafChild() : curr->firstLeafChild();

[leviw_travelin_and_unemployed, 2015/06/22 18:22:42]

I understand you're moving this code around. If we end with a break, won't the
lineBreakObj() on RootInlineBox point to that without having to drill down and
look for the first/last leaf child?

[rhogan, 2015/06/22 20:27:15]

Had to look it up: lineBreakObj() is the object *after* the line break. <br>'s
don't result in lineBreakObj() getting set with the br object, it would only get
one if there was another br object after it. 

Ah, line layout.

+    return lastBox && lastBox->layoutObject().isBR() && lastBox->layoutObject().style()->clear() != CNONE;
+}
+
 void LayoutBlockFlow::determineEndPosition(LineLayoutState& layoutState, RootInlineBox* startLine, InlineIterator& cleanLineStart, BidiStatus& cleanLineBidiStatus)
 {
     ASSERT(!layoutState.endLine());
@@ -1763,6 +1767,8 @@ void LayoutBlockFlow::determineEndPosition(LineLayoutState& layoutState, RootInl
             checkFloatsInCleanLine(curr, layoutState.floats(), floatIndex, encounteredNewFloat, dirtiedByFloat);
             if (encounteredNewFloat)
                 return;
+            if (lineBoxHasBRWithClearance(curr))
+                return;
         }
         if (curr->isDirty())
             last = nullptr;
@@ -1837,11 +1843,6 @@ bool LayoutBlockFlow::matchedEndLine(LineLayoutState& layoutState, const InlineB
         if (resolver.status() != endLineStatus)
             return false;
 
-        // A trailing BR can be collapsed as it usually doesn't contribute to the height,
-        // but if it has a clear style we need to force it to layout in the context of floats
-        // to honor that style.
-        if (layoutState.containsBRWithClear() && containsFloats())
-            return false;
         return checkPaginationAndFloatsAtEndLine(layoutState);
     }