move SkPath direction-as-computed into SkPathPriv

gm/convex_all_line_paths.cpp

Index: gm/convex_all_line_paths.cpp
diff --git a/gm/convex_all_line_paths.cpp b/gm/convex_all_line_paths.cpp
index 81b98b88f8d07e82cf5bcf4886490015cc6c6ab5..a93a7f6e4722c0dac138225e99f7882881e437fc 100644
--- a/gm/convex_all_line_paths.cpp
+++ b/gm/convex_all_line_paths.cpp
@@ -6,6 +6,7 @@
  */
 
 #include "gm.h"
+#include "SkPathPriv.h"
 
 static void create_ngon(int n, SkPoint* pts, SkScalar width, SkScalar height) {
     float angleStep = 360.0f / n, angle = 0.0f, sin, cos;
@@ -237,9 +238,9 @@ protected:
         // of the GMs rows.
         SkASSERT(path.isConvex());
         SkASSERT(SkPath::kLine_SegmentMask == path.getSegmentMasks());
-        SkPath::Direction actualDir;
-        SkASSERT(path.cheapComputeDirection(&actualDir));
-        SkASSERT(dir == actualDir);
+        SkPathPriv::FirstDirection actualDir;
+        SkASSERT(SkPathPriv::CheapComputeFirstDirection(path, &actualDir));
+        SkASSERT(SkPathPriv::AsFirstDirection(dir) == actualDir);
         SkRect bounds = path.getBounds();
         SkASSERT(SkScalarNearlyEqual(bounds.centerX(), 0.0f));
         SkASSERT(bounds.height() <= kMaxPathHeight);