Bug 520992, Followup 1: Simplify code in nsDOMComputedStyle for box-sizing adjustment for clarity. [r=me]

layout/style/nsComputedDOMStyle.cpp

@@ -386,26 +386,17 @@ nsComputedDOMStyle::GetAdjustedValuesForBoxSizing()
   nscoord borderPaddingTop = 0;
   nscoord borderPaddingBottom = 0;
 
-  nsMargin border = mInnerFrame->GetUsedBorder();
-  nsMargin padding = mInnerFrame->GetUsedPadding();
-
+  nsMargin adjustment;
   switch(stylePos->mBoxSizing) {
     case NS_STYLE_BOX_SIZING_BORDER:
-      borderPaddingLeft += border.left;
-      borderPaddingRight += border.right;
-      borderPaddingTop += border.top;
-      borderPaddingBottom += border.bottom;
+      adjustment += mInnerFrame->GetUsedBorder();
       // fall through
 
     case NS_STYLE_BOX_SIZING_PADDING:
-      borderPaddingLeft += padding.left;
-      borderPaddingRight += padding.right;
-      borderPaddingTop += padding.top;
-      borderPaddingBottom += padding.bottom;
+      adjustment += mInnerFrame->GetUsedPadding();
   }
 
-  return nsMargin(borderPaddingTop, borderPaddingRight, borderPaddingBottom,
-                  borderPaddingLeft);
+  return adjustment;
 }
 
 /* static */