Add support for the object-position CSS property.

Source/core/rendering/style/RenderStyle.h

Index: Source/core/rendering/style/RenderStyle.h
diff --git a/Source/core/rendering/style/RenderStyle.h b/Source/core/rendering/style/RenderStyle.h
index fa739b695a3b8fe99d867e7a82748837cd720064..05c17e07431f801ffe7d352d23e8553ed75e4cdc 100644
--- a/Source/core/rendering/style/RenderStyle.h
+++ b/Source/core/rendering/style/RenderStyle.h
@@ -819,6 +819,7 @@ public:
     TextOrientation textOrientation() const { return static_cast<TextOrientation>(rareInheritedData->m_textOrientation); }
 
     ObjectFit objectFit() const { return static_cast<ObjectFit>(rareNonInheritedData->m_objectFit); }
+    LengthPoint objectPosition() const { return rareNonInheritedData->m_objectPosition; }
 
     // Return true if any transform related property (currently transform, transformStyle3D or perspective)
     // indicates that we are transforming
@@ -1254,6 +1255,7 @@ public:
     bool setTextOrientation(TextOrientation);
 
     void setObjectFit(ObjectFit f) { SET_VAR(rareNonInheritedData, m_objectFit, f); }
+    void setObjectPosition(LengthPoint position) { SET_VAR(rareNonInheritedData, m_objectPosition, position); }
 
     void setRubyPosition(RubyPosition position) { SET_VAR(rareInheritedData, m_rubyPosition, position); }
 
@@ -1461,6 +1463,7 @@ public:
     static TextCombine initialTextCombine() { return TextCombineNone; }
     static TextOrientation initialTextOrientation() { return TextOrientationVerticalRight; }
     static ObjectFit initialObjectFit() { return ObjectFitFill; }
+    static LengthPoint initialObjectPosition() { return LengthPoint(Length(50.0, Percent), Length(50.0, Percent)); }
     static EDisplay initialDisplay() { return INLINE; }
     static EEmptyCell initialEmptyCells() { return SHOW; }
     static EFloat initialFloating() { return NoFloat; }