Add scale and skew to C canvas API

src/c/sk_surface.cpp

Index: src/c/sk_surface.cpp
diff --git a/src/c/sk_surface.cpp b/src/c/sk_surface.cpp
index 1cd4f3d87e37c84de4753cfb722c53f314c0baff..05f4ef7ab3356fad0be9763a8cf2d7b79374157c 100644
--- a/src/c/sk_surface.cpp
+++ b/src/c/sk_surface.cpp
@@ -308,6 +308,14 @@ void sk_canvas_scale(sk_canvas_t* ccanvas, float sx, float sy) {
     AsCanvas(ccanvas)->scale(sx, sy);
 }
 
+void sk_canvas_rotate(sk_canvas_t* ccanvas, float degrees) {
+    AsCanvas(ccanvas)->rotate(degrees);
+}
+
+void sk_canvas_skew(sk_canvas_t* ccanvas, float sx, float sy) {
+    AsCanvas(ccanvas)->skew(sx, sy);
+}
+
 void sk_canvas_draw_paint(sk_canvas_t* ccanvas, const sk_paint_t* cpaint) {
     AsCanvas(ccanvas)->drawPaint(AsPaint(*cpaint));
 }