Remove unnecessary static function

cc/trees/layer_sorter.cc

Index: cc/trees/layer_sorter.cc
diff --git a/cc/trees/layer_sorter.cc b/cc/trees/layer_sorter.cc
index e171fe01120f6389931b1acb403581968e7126db..37e41de9c9bb8ef111f351c1c75bd4e42759c90f 100644
--- a/cc/trees/layer_sorter.cc
+++ b/cc/trees/layer_sorter.cc
@@ -23,11 +23,6 @@ namespace cc {
 // the test scene went away.
 const float k_layer_epsilon = 1e-4f;
 
-inline static float PerpProduct(const gfx::Vector2dF& u,
-                                const gfx::Vector2dF& v) {
-  return u.x() * v.y() - u.y() * v.x();
-}
-
 // Tests if two edges defined by their endpoints (a,b) and (c,d) intersect.
 // Returns true and the point of intersection if they do and false otherwise.
 static bool EdgeEdgeTest(const gfx::PointF& a,
@@ -39,7 +34,7 @@ static bool EdgeEdgeTest(const gfx::PointF& a,
   gfx::Vector2dF v = d - c;
   gfx::Vector2dF w = a - c;
 
-  float denom = PerpProduct(u, v);
+  float denom = gfx::CrossProduct(u, v);

[danakj, 2014/08/06 13:45:55]

this method returns a double, so you'll get narrowing errors storing it directly
into a float. you'll have to cast it.

[hj.r.chung, 2014/08/07 01:55:12]

While looking into the code, I've found that there aren't any other callers for
CrossProduct(Vector2dF&, Vector2dF&). Do you think it will be ok to change
CrossProduct() to return float instead of double? Will there be any cases that
need double precision in the future?

 
   // If denom == 0 then the edges are parallel. While they could be overlapping
   // we don't bother to check here as the we'll find their intersections from
@@ -47,11 +42,11 @@ static bool EdgeEdgeTest(const gfx::PointF& a,
   if (!denom)
     return false;
 
-  float s = PerpProduct(v, w) / denom;
+  float s = gfx::CrossProduct(v, w) / denom;
   if (s < 0.f || s > 1.f)
     return false;
 
-  float t = PerpProduct(u, w) / denom;
+  float t = gfx::CrossProduct(u, w) / denom;
   if (t < 0.f || t > 1.f)
     return false;