[CSS Shapes] shape-margin in percentage units always computes to 0px

Source/core/rendering/shapes/ShapeInfo.cpp

Index: Source/core/rendering/shapes/ShapeInfo.cpp
diff --git a/Source/core/rendering/shapes/ShapeInfo.cpp b/Source/core/rendering/shapes/ShapeInfo.cpp
index 22879e8f8f84a3b3abcedfb380eec05d93737a5d..2325ac5378965dff520d6ea91975010536723358 100644
--- a/Source/core/rendering/shapes/ShapeInfo.cpp
+++ b/Source/core/rendering/shapes/ShapeInfo.cpp
@@ -33,6 +33,8 @@
 #include "core/rendering/RenderBlock.h"
 #include "core/rendering/RenderImage.h"
 
+#include "platform/LengthFunctions.h"
+
 namespace WebCore {
 
 template<class RenderType>
@@ -112,7 +114,8 @@ const Shape& ShapeInfo<RenderType>::computedShape() const
         return *shape;
 
     WritingMode writingMode = this->styleForWritingMode()->writingMode();
-    Length margin = m_renderer.style()->shapeMargin();
+    LayoutUnit maximumValue = m_renderer.containingBlock() ? m_renderer.containingBlock()->contentWidth() : LayoutUnit();

[Bem Jones-Bey (adobe), 2014/04/04 23:03:53]

Isn't there an implicit conversion from LayoutUnit to float? If so, wouldn't
using 0.0f instead of LayoutUnit() here mean that you could store this in a
float and not need the explicit toFloat() below?

[leviw_travelin_and_unemployed, 2014/04/07 17:54:38]

We're actually working on killing the implicit conversions to/from LayoutUnits,
as they're quite prone to misuse.

+    float margin = floatValueForLength(m_renderer.style()->shapeMargin(), maximumValue.toFloat());
     float shapeImageThreshold = m_renderer.style()->shapeImageThreshold();
     const ShapeValue* shapeValue = this->shapeValue();
     ASSERT(shapeValue);