[CSS Shapes] inset does not properly clamp large corner radii

Source/core/rendering/style/RenderStyle.cpp

Index: Source/core/rendering/style/RenderStyle.cpp
diff --git a/Source/core/rendering/style/RenderStyle.cpp b/Source/core/rendering/style/RenderStyle.cpp
index f1230077c8fa4ee75a4b250e81a0f95d5ce1a66a..e61d06c4e5c4a7e77e0f337bb29b65520c57431f 100644
--- a/Source/core/rendering/style/RenderStyle.cpp
+++ b/Source/core/rendering/style/RenderStyle.cpp
@@ -37,6 +37,7 @@
 #include "platform/LengthFunctions.h"
 #include "platform/fonts/Font.h"
 #include "platform/fonts/FontSelector.h"
+#include "platform/geometry/FloatRoundedRect.h"
 #include "wtf/MathExtras.h"
 
 using namespace std;
@@ -926,38 +927,6 @@ static RoundedRect::Radii calcRadiiFor(const BorderData& border, IntSize size)
             valueForLength(border.bottomRight().height(), size.height())));
 }
 
-static float calcConstraintScaleFor(const IntRect& rect, const RoundedRect::Radii& radii)
-{
-    // Constrain corner radii using CSS3 rules:
-    // http://www.w3.org/TR/css3-background/#the-border-radius
-
-    float factor = 1;
-    unsigned radiiSum;
-
-    // top
-    radiiSum = static_cast<unsigned>(radii.topLeft().width()) + static_cast<unsigned>(radii.topRight().width()); // Casts to avoid integer overflow.
-    if (radiiSum > static_cast<unsigned>(rect.width()))
-        factor = min(static_cast<float>(rect.width()) / radiiSum, factor);
-
-    // bottom
-    radiiSum = static_cast<unsigned>(radii.bottomLeft().width()) + static_cast<unsigned>(radii.bottomRight().width());
-    if (radiiSum > static_cast<unsigned>(rect.width()))
-        factor = min(static_cast<float>(rect.width()) / radiiSum, factor);
-
-    // left
-    radiiSum = static_cast<unsigned>(radii.topLeft().height()) + static_cast<unsigned>(radii.bottomLeft().height());
-    if (radiiSum > static_cast<unsigned>(rect.height()))
-        factor = min(static_cast<float>(rect.height()) / radiiSum, factor);
-
-    // right
-    radiiSum = static_cast<unsigned>(radii.topRight().height()) + static_cast<unsigned>(radii.bottomRight().height());
-    if (radiiSum > static_cast<unsigned>(rect.height()))
-        factor = min(static_cast<float>(rect.height()) / radiiSum, factor);
-
-    ASSERT(factor <= 1);
-    return factor;
-}
-
 StyleImage* RenderStyle::listStyleImage() const { return rareInheritedData->listStyleImage.get(); }
 void RenderStyle::setListStyleImage(PassRefPtr<StyleImage> v)
 {
@@ -981,7 +950,7 @@ RoundedRect RenderStyle::getRoundedBorderFor(const LayoutRect& borderRect, bool
     RoundedRect roundedRect(snappedBorderRect);
     if (hasBorderRadius()) {
         RoundedRect::Radii radii = calcRadiiFor(surround->border, snappedBorderRect.size());
-        radii.scale(calcConstraintScaleFor(snappedBorderRect, radii));
+        radii.scale(calcBorderRadiiConstraintScaleFor(borderRect, radii));
         roundedRect.includeLogicalEdges(radii, isHorizontalWritingMode(), includeLogicalLeftEdge, includeLogicalRightEdge);
     }
     return roundedRect;
@@ -1625,4 +1594,36 @@ void RenderStyle::setBorderImageOutset(const BorderImageLengthBox& outset)
     surround.access()->border.m_image.setOutset(outset);
 }
 
+float calcBorderRadiiConstraintScaleFor(const FloatRect& rect, const FloatRoundedRect::Radii& radii)
+{
+    // Constrain corner radii using CSS3 rules:
+    // http://www.w3.org/TR/css3-background/#the-border-radius
+
+    float factor = 1;
+    float radiiSum;
+
+    // top
+    radiiSum = radii.topLeft().width() + radii.topRight().width(); // Casts to avoid integer overflow.
+    if (radiiSum > rect.width())
+        factor = std::min(rect.width() / radiiSum, factor);
+
+    // bottom
+    radiiSum = radii.bottomLeft().width() + radii.bottomRight().width();
+    if (radiiSum > rect.width())
+        factor = std::min(rect.width() / radiiSum, factor);
+
+    // left
+    radiiSum = radii.topLeft().height() + radii.bottomLeft().height();
+    if (radiiSum > rect.height())
+        factor = std::min(rect.height() / radiiSum, factor);
+
+    // right
+    radiiSum = radii.topRight().height() + radii.bottomRight().height();
+    if (radiiSum > rect.height())
+        factor = std::min(rect.height() / radiiSum, factor);
+
+    ASSERT(factor <= 1);
+    return factor;
+}
+
 } // namespace WebCore