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 2c268147f8a9cd8f09358227c6141f61a389e4b8..ce0e7524c9c1aa964f19625bee9c92eac4327fcd 100644
--- a/Source/core/rendering/style/RenderStyle.h
+++ b/Source/core/rendering/style/RenderStyle.h
@@ -829,6 +829,7 @@ 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
@@ -1267,6 +1268,7 @@ 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); }
 
@@ -1477,6 +1479,7 @@ 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; }