[CSS Shapes] Serialize circle/ellipse positions

Source/core/css/CSSBasicShapes.cpp

Index: Source/core/css/CSSBasicShapes.cpp
diff --git a/Source/core/css/CSSBasicShapes.cpp b/Source/core/css/CSSBasicShapes.cpp
index e7f03f5c31abc281179e60dc69cf76fcbe92c7c4..147cda676df7f868db918470c3dafbaffe5c0ea9 100644
--- a/Source/core/css/CSSBasicShapes.cpp
+++ b/Source/core/css/CSSBasicShapes.cpp
@@ -30,7 +30,9 @@
 #include "config.h"
 #include "core/css/CSSBasicShapes.h"
 
+#include "core/css/CSSValuePool.h"
 #include "core/css/Pair.h"
+#include "platform/Length.h"
 #include "wtf/text/StringBuilder.h"
 
 using namespace WTF;
@@ -131,11 +133,56 @@ static String buildCircleString(const String& radius, const String& centerX, con
     return result.toString();
 }
 
+static String serializePositionOffset(const Pair& offset, const Pair& other)
+{
+    if ((offset.first()->getValueID() == CSSValueLeft && other.first()->getValueID() == CSSValueTop)
+        || (offset.first()->getValueID() == CSSValueTop && other.first()->getValueID() == CSSValueLeft))
+        return offset.second()->cssText();
+    return offset.cssText();
+}
+
+static PassRefPtr<CSSPrimitiveValue> buildSerializablePositionOffset(PassRefPtr<CSSPrimitiveValue> offset, CSSValueID defaultSide)
+{
+    CSSValueID side = defaultSide;
+    RefPtr<CSSPrimitiveValue> amount;
+
+    if (!offset) {
+        side = CSSValueCenter;
+    } else if (offset->isValueID()) {
+        side = offset->getValueID();
+    } else if (Pair* pair = offset->getPairValue()) {
+        side = pair->first()->getValueID();
+        amount = pair->second();
+    } else {
+        amount = offset;
+    }
+
+    if (side == CSSValueCenter) {
+        side = defaultSide;
+        amount = cssValuePool().createValue(Length(50, Percent));
+    } else if ((side == CSSValueRight || side == CSSValueBottom)
+        && amount->isPercentage()) {
+        side = defaultSide;
+        amount = cssValuePool().createValue(Length(100 - amount->getFloatValue(), Percent));
+    } else if (amount->isLength() && !amount->getFloatValue()) {
+        if (side == CSSValueRight || side == CSSValueBottom)
+            amount = cssValuePool().createValue(Length(100, Percent));
+        else
+            amount = cssValuePool().createValue(Length(0, Percent));
+        side = defaultSide;
+    }
+
+    return cssValuePool().createValue(Pair::create(cssValuePool().createValue(side), amount.release(), Pair::KeepIdenticalValues));
+}
+
 String CSSBasicShapeCircle::cssText() const
 {
+    RefPtr<CSSPrimitiveValue> normalizedCX = buildSerializablePositionOffset(m_centerX, CSSValueLeft);
+    RefPtr<CSSPrimitiveValue> normalizedCY = buildSerializablePositionOffset(m_centerY, CSSValueTop);
+
     return buildCircleString(m_radius ? m_radius->cssText() : String(),
-        m_centerX ? m_centerX->cssText() : String(),
-        m_centerY ? m_centerY->cssText() : String(),
+        serializePositionOffset(*normalizedCX->getPairValue(), *normalizedCY->getPairValue()),
+        serializePositionOffset(*normalizedCY->getPairValue(), *normalizedCX->getPairValue()),
         m_layoutBox ? m_layoutBox->cssText() : String());
 }
 
@@ -225,10 +272,13 @@ static String buildEllipseString(const String& radiusX, const String& radiusY, c
 
 String CSSBasicShapeEllipse::cssText() const
 {
+    RefPtr<CSSPrimitiveValue> normalizedCX = buildSerializablePositionOffset(m_centerX, CSSValueLeft);
+    RefPtr<CSSPrimitiveValue> normalizedCY = buildSerializablePositionOffset(m_centerY, CSSValueTop);
+
     return buildEllipseString(m_radiusX ? m_radiusX->cssText() : String(),
         m_radiusY ? m_radiusY->cssText() : String(),
-        m_centerX ? m_centerX->cssText() : String(),
-        m_centerY ? m_centerY->cssText() : String(),
+        serializePositionOffset(*normalizedCX->getPairValue(), *normalizedCY->getPairValue()),
+        serializePositionOffset(*normalizedCY->getPairValue(), *normalizedCX->getPairValue()),
         m_layoutBox ? m_layoutBox->cssText() : String());
 }