BR styled clear is ignored while partially relayouting.

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 90671e46dfb6dd6edd0603c695ac1853c4caf191..e960ca82f457a365bfa5a6424edb56cdf3d31685 100644
--- a/Source/core/layout/LayoutBlockFlowLine.cpp
+++ b/Source/core/layout/LayoutBlockFlowLine.cpp
@@ -1563,6 +1563,9 @@ 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);
 
@@ -1858,6 +1861,12 @@ bool LayoutBlockFlow::matchedEndLine(LineLayoutState& layoutState, const InlineB
     if (resolver.position() == endLineStart) {
         if (resolver.status() != endLineStatus)
             return false;
+
+        // For partial layout where the block contains floats, the end line here is the last visible one.
+        // It misleads shorter height of the block than expected. We should check until the end line

[leviw_travelin_and_unemployed, 2015/05/20 21:22:29]

"It misleads shorter height of the block than expected" doesn't make sense :-/

[changseok, 2015/05/21 09:32:40]

Hrm.. what does not make sense to you? If you could point it out a little bit
more in depth, it would be much helpful.

Not sure of your thought though.. then how about this?
"For partial layout where the block contains floats, the end line here is the
last visible one. Due to calculating only these visible lines for the block
height, invisible br having clear style is ignored so that it causes shorter
height of the block than expected. We should check until the end line of the
block for the case."

[leviw_travelin_and_unemployed, 2015/05/21 17:49:50]

It's not proper English... "shorter height of the block" is not a sensible
direct object for misleads...
Last visible float?
What do you mean "visible" here?

I think what you're trying to say is that 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.

[changseok, 2015/05/22 08:47:35]

Oops, English is not my mother language so I used to make this kind of errors.
Sorry about that. :P
I meant last visible line.
What I meant for visible was something to have actual contents so it takes a
visual region. For example, empty span, <span></span> is not visible, but
<span>text</span> is visible.
Yeah. same context, but your summary is neater. May I just use yours?

+        // of the block for the case.
+        if (layoutState.containsBRWithClear() && containsFloats())
+            return false;
         return checkPaginationAndFloatsAtEndLine(layoutState);
     }