move private test for sect_with_horizontal into unittests

src/core/SkLineClipper.cpp

Index: src/core/SkLineClipper.cpp
diff --git a/src/core/SkLineClipper.cpp b/src/core/SkLineClipper.cpp
index 189f03ac735123f7bfa1f3ae7e3d9d03bdde562c..9acb657679b30ccf808cc40c79c986aac968cd66 100644
--- a/src/core/SkLineClipper.cpp
+++ b/src/core/SkLineClipper.cpp
@@ -22,6 +22,21 @@ template <typename T> T pin_unsorted(T value, T limit0, T limit1) {
     return value;
 }
 
+// This is an example of why we need to pin the result computed in
+// sect_with_horizontal. If we didn't explicitly pin, is_between_unsorted would
+// fail.
+//
+#if 0
+static void sect_with_horizontal_test_for_pin_results() {
+    const SkPoint pts[] = {
+        { -540000,    -720000 },
+        { -9.10000017e-05f, 9.99999996e-13f }
+    };
+    float x = sect_with_horizontal(pts, 0);
+    SkASSERT(is_between_unsorted(x, pts[0].fX, pts[1].fX));
+}
+#endif
+
 // return X coordinate of intersection with horizontal line at Y
 static SkScalar sect_with_horizontal(const SkPoint src[2], SkScalar Y) {
     SkScalar dy = src[1].fY - src[0].fY;
@@ -157,34 +172,8 @@ static bool is_between_unsorted(SkScalar value,
 }
 #endif
 
-#ifdef SK_DEBUG
-// This is an example of why we need to pin the result computed in
-// sect_with_horizontal. If we didn't explicitly pin, is_between_unsorted would
-// fail.
-//
-static void sect_with_horizontal_test_for_pin_results() {
-    const SkPoint pts[] = {
-        { -540000,    -720000 },
-        { -9.10000017e-05f, 9.99999996e-13f }
-    };
-    float x = sect_with_horizontal(pts, 0);
-    SkASSERT(is_between_unsorted(x, pts[0].fX, pts[1].fX));
-}
-#endif
-
 int SkLineClipper::ClipLine(const SkPoint pts[], const SkRect& clip, SkPoint lines[],
                             bool canCullToTheRight) {
-
-#ifdef SK_DEBUG
-    {
-        static bool gOnce;

[mtklein, 2016/08/17 13:12:53]

If you want to keep this and make it thread safe, you should be able to just
write:

    static SkOnce once;
    once(sect_with_horizontal_test_for_pin_results);

-        if (!gOnce) {
-            sect_with_horizontal_test_for_pin_results();
-            gOnce = true;
-        }
-    }
-#endif
-
     int index0, index1;
 
     if (pts[0].fY < pts[1].fY) {