[SVG2] Add support for the 'turn' unit in <angle>.

LayoutTests/svg/css/svg-angle-turn-expected.svg

Index: LayoutTests/svg/css/svg-angle-turn-expected.svg
diff --git a/LayoutTests/svg/css/svg-angle-turn-expected.svg b/LayoutTests/svg/css/svg-angle-turn-expected.svg
new file mode 100644
index 0000000000000000000000000000000000000000..cdb4fb2d47c7b71bc9e30fddcc3b11eacf36eecd
--- /dev/null
+++ b/LayoutTests/svg/css/svg-angle-turn-expected.svg
@@ -0,0 +1,32 @@
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="800" height="600">
+	<defs>
+		<marker id="turn0.2" refY="5" viewBox="0 0 10 10" orient="72deg">
+			<path d="M0 0l10 5 -10 5z"/>
+		</marker>
+		<marker id="turn0.5" refY="5" viewBox="0 0 10 10" orient="180deg">
+			<path d="M0 0l10 5 -10 5z"/>
+		</marker>
+		<marker id="turn1" refY="5" viewBox="0 0 10 10" orient="360deg">
+			<path d="M0 0l10 5 -10 5z"/>
+		</marker>
+		<marker id="turn1.7" refY="5" viewBox="0 0 10 10" orient="612deg">
+			<path d="M0 0l10 5 -10 5z"/>
+		</marker>
+		<style>
+			.test { 
+				stroke: black;
+				stroke-width: 10px;
+			}
+			
+			#t1 { marker-end: url(#turn0.2); }
+			#t2 { marker-end: url(#turn0.5); }
+			#t3 { marker-end: url(#turn1); }
+			#t4 { marker-end: url(#turn1.7); }
+		</style>
+	</defs>
+
+	<path id="t1" class="test" d="M10 40h200" />
+	<path id="t2" class="test" d="M10 80h200" />
+	<path id="t3" class="test" d="M10 120h200" />
+	<path id="t4" class="test" d="M10 160h200" />
+</svg>