Marquee width should not change a fixed width of its container.

Source/core/layout/LayoutBlock.cpp

Index: Source/core/layout/LayoutBlock.cpp
diff --git a/Source/core/layout/LayoutBlock.cpp b/Source/core/layout/LayoutBlock.cpp
index c717f16cd731914f84449fa5e7454a712bf67b39..eb9988a978d0d919005d6c07cae48aaac3c3dc05 100644
--- a/Source/core/layout/LayoutBlock.cpp
+++ b/Source/core/layout/LayoutBlock.cpp
@@ -38,6 +38,7 @@
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
+#include "core/html/HTMLMarqueeElement.h"
 #include "core/layout/HitTestLocation.h"
 #include "core/layout/HitTestResult.h"
 #include "core/layout/LayoutAnalyzer.h"
@@ -2007,6 +2008,9 @@ void LayoutBlock::computeIntrinsicLogicalWidths(LayoutUnit& minLogicalWidth, Lay
 
     maxLogicalWidth = std::max(minLogicalWidth, maxLogicalWidth);
 
+    if (isHTMLMarqueeElement(node()) && toHTMLMarqueeElement(node())->isHorizontal())
+        minLogicalWidth = 0;

[mstensho (USE GERRIT), 2015/06/24 08:24:37]

minLogicalWidth = LayoutUnit() is cheaper (or you'll end up in setValue() and
saturatedSet() for no reason).

[changseok, 2015/06/25 06:41:34]

Done.

+
     if (isTableCell()) {
         Length tableCellWidth = toLayoutTableCell(this)->styleOrColLogicalWidth();
         if (tableCellWidth.isFixed() && tableCellWidth.value() > 0)