Negative or zero radius for <area shape=circle> gives an empty shape

third_party/WebKit/Source/core/html/HTMLAreaElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLAreaElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLAreaElement.cpp b/third_party/WebKit/Source/core/html/HTMLAreaElement.cpp
index 1c096e2a2880d63decc0c9150b421cf4e5db70a9..cf0c5c1ecba4dfbcf563a94c3c34d3a529091b7f 100644
--- a/third_party/WebKit/Source/core/html/HTMLAreaElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLAreaElement.cpp
@@ -160,7 +160,7 @@ Path HTMLAreaElement::getRegion(const LayoutSize& size) const
         }
         break;
     case Circle:
-        if (m_coords.size() >= 3) {
+        if (m_coords.size() >= 3 && m_coords[2].value() > 0) {
             float r = clampCoordinate(m_coords[2]);
             path.addEllipse(FloatRect(clampCoordinate(m_coords[0]) - r, clampCoordinate(m_coords[1]) - r, 2 * r, 2 * r));
         }