Factor out common BorderImageLength code in CSSToStyleMap

Source/core/rendering/style/BorderImageLengthBox.h

Index: Source/core/rendering/style/BorderImageLengthBox.h
diff --git a/Source/core/rendering/style/BorderImageLengthBox.h b/Source/core/rendering/style/BorderImageLengthBox.h
index 8d417df8ace36cdeb6e99463720066c1fd3569aa..436846ac9b92eda85b3403db1a97f49bcd85987b 100644
--- a/Source/core/rendering/style/BorderImageLengthBox.h
+++ b/Source/core/rendering/style/BorderImageLengthBox.h
@@ -41,23 +41,19 @@ namespace WebCore {
 // http://www.w3.org/TR/css3-background/#border-image-outset
 class BorderImageLengthBox {
 public:
-    BorderImageLengthBox()
+    BorderImageLengthBox(Length length)
+        : m_left(length)
+        , m_right(length)
+        , m_top(length)
+        , m_bottom(length)
     {
     }
 
-    BorderImageLengthBox(Length top, Length right, Length bottom, Length left)
-        : m_left(left)
-        , m_right(right)
-        , m_top(top)
-        , m_bottom(bottom)
-    {
-    }
-
-    BorderImageLengthBox(double top, double right, double bottom, double left)
-        : m_left(left)
-        , m_right(right)
-        , m_top(top)
-        , m_bottom(bottom)
+    BorderImageLengthBox(double number)
+        : m_left(number)
+        , m_right(number)
+        , m_top(number)
+        , m_bottom(number)
     {
     }
 
@@ -75,11 +71,6 @@ public:
     const BorderImageLength& top() const { return m_top; }
     const BorderImageLength& bottom() const { return m_bottom; }
 
-    void setLeft(const BorderImageLength& left) { m_left = left; }
-    void setRight(const BorderImageLength& right) { m_right = right; }
-    void setTop(const BorderImageLength& top) { m_top = top; }
-    void setBottom(const BorderImageLength& bottom) { m_bottom = bottom; }
-
     bool operator==(const BorderImageLengthBox& other) const
     {
         return m_left == other.m_left && m_right == other.m_right