[CSS Shapes] inset args and radial args should serialize to the simplest form

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 72bfcef26d5af2c9cc68b41243562c6bc75579b9..c65717e6bf47f1bdf0db2eb386d97fee295ab28c 100644
--- a/Source/core/css/CSSBasicShapes.cpp
+++ b/Source/core/css/CSSBasicShapes.cpp
@@ -296,43 +296,67 @@ static String buildInsetString(const String& top, const String& right, const Str
     StringBuilder result;
     result.appendLiteral(opening);
     result.append(top);
-    if (!right.isNull()) {
+    bool showLeftArg = !left.isNull() && left != right;
+    bool showBottomArg = !bottom.isNull() && (bottom != top || showLeftArg);
+    bool showRightArg = !right.isNull() && (right != top || showBottomArg);
+    if (showRightArg) {
         result.appendLiteral(separator);
         result.append(right);
     }
-    if (!bottom.isNull()) {
+    if (showBottomArg) {
         result.appendLiteral(separator);
         result.append(bottom);
     }
-    if (!left.isNull()) {
+    if (showLeftArg) {
         result.appendLiteral(separator);
         result.append(left);
     }
 
     if (!topLeftRadiusWidth.isNull() && !topLeftRadiusHeight.isNull()) {
-        result.appendLiteral(separator);
-        result.appendLiteral(cornersSeparator);
-        result.appendLiteral(separator);
-
-        result.append(topLeftRadiusWidth);
-        result.appendLiteral(separator);
-        result.append(topRightRadiusWidth);
-        result.appendLiteral(separator);
-        result.append(bottomRightRadiusWidth);
-        result.appendLiteral(separator);
-        result.append(bottomLeftRadiusWidth);
-
-        result.appendLiteral(separator);
-        result.appendLiteral("/");
-        result.appendLiteral(separator);
-
-        result.append(topLeftRadiusHeight);
-        result.appendLiteral(separator);
-        result.append(topRightRadiusHeight);
-        result.appendLiteral(separator);
-        result.append(bottomRightRadiusHeight);
-        result.appendLiteral(separator);
-        result.append(bottomLeftRadiusHeight);
+        bool showHorizontalBottomLeft = topRightRadiusWidth != bottomLeftRadiusWidth;
+        bool showHorizontalBottomRight = showHorizontalBottomLeft || (bottomRightRadiusWidth != topLeftRadiusWidth);
+        bool showHorizontalTopRight = showHorizontalBottomRight || (topRightRadiusWidth != topLeftRadiusWidth);
+
+        Vector<String> horizontalRadii;

[Bear Travis, 2014/04/08 19:08:35]

Would it be possible / worth it to factor out the horizontalRadii and
verticalRadii building into a helper method that calculates the booleans and
adds the requisite strings to the vector?

+        horizontalRadii.append(topLeftRadiusWidth);
+        if (showHorizontalTopRight)
+            horizontalRadii.append(topRightRadiusWidth);
+        if (showHorizontalBottomRight)
+            horizontalRadii.append(bottomRightRadiusWidth);
+        if (showHorizontalBottomLeft)
+            horizontalRadii.append(bottomLeftRadiusWidth);
+
+        bool showVerticalBottomLeft = topRightRadiusHeight != bottomLeftRadiusHeight;
+        bool showVerticalBottomRight = showVerticalBottomLeft || (bottomRightRadiusHeight != topLeftRadiusHeight);
+        bool showVerticalTopRight = showVerticalBottomRight || (topRightRadiusHeight != topLeftRadiusHeight);
+
+        Vector<String> verticalRadii;
+        verticalRadii.append(topLeftRadiusHeight);
+        if (showVerticalTopRight)
+            verticalRadii.append(topRightRadiusHeight);
+        if (showVerticalBottomRight)
+            verticalRadii.append(bottomRightRadiusHeight);
+        if (showVerticalBottomLeft)
+            verticalRadii.append(bottomLeftRadiusHeight);
+
+        if (!(horizontalRadii.size() == 1 && horizontalRadii[0] == "0px" && verticalRadii[0] == "0px")) {

[Bear Travis, 2014/04/08 19:08:35]

I think this also needs to check for verticalRadii.size being 1, otherwise
you'll miss the case of inset(10px round 0px / 0px 10px). Might be worth
factoring this into a method so you can specify what you're testing, eg
'areDefaultCornerRadii' or some such.

+            result.appendLiteral(separator);
+            result.appendLiteral(cornersSeparator);
+
+            for (size_t i = 0; i < horizontalRadii.size(); ++i) {
+                result.appendLiteral(separator);
+                result.append(horizontalRadii[i]);
+            }
+            if (horizontalRadii != verticalRadii) {
+                result.appendLiteral(separator);
+                result.appendLiteral("/");
+
+                for (size_t i = 0; i < verticalRadii.size(); ++i) {
+                    result.appendLiteral(separator);
+                    result.append(verticalRadii[i]);
+                }
+            }
+        }
     }
     result.append(')');