Revert of Remove unnecessary static function (patchset #2 of...

Revert of Remove unnecessary static function (patchset #2 of https://codereview.chromium.org/444983002/)

Reason for revert:
Perf regression, due to the method no longer being inline, and using doubles instead of floats.

Original issue's description:
> Remove unnecessary static function
> 
> Use gfx::CrossProduct() instead of defining a new static function.
> 
> BUG=
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=288372

TBR=enne@chromium.org,heejin.r.chung@samsung.com
NOTREECHECKS=true
NOTRY=true
BUG=402552

Review URL: https://codereview.chromium.org/471113002

Cr-Commit-Position: refs/heads/master@{#289645}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@289645 0039d316-1c4b-4281-b951-d872f2087c98

cc/trees/layer_sorter.cc

@@ -23,6 +23,11 @@ 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,
@@ -34,7 +39,7 @@ static bool EdgeEdgeTest(const gfx::PointF& a,
   gfx::Vector2dF v = d - c;
   gfx::Vector2dF w = a - c;
 
-  float denom = static_cast<float>(gfx::CrossProduct(u, v));
+  float denom = PerpProduct(u, v);
 
   // 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
@@ -42,11 +47,11 @@ static bool EdgeEdgeTest(const gfx::PointF& a,
   if (!denom)
     return false;
 
-  float s = static_cast<float>(gfx::CrossProduct(v, w)) / denom;
+  float s = PerpProduct(v, w) / denom;
   if (s < 0.f || s > 1.f)
     return false;
 
-  float t = static_cast<float>(gfx::CrossProduct(u, w)) / denom;
+  float t = PerpProduct(u, w) / denom;
   if (t < 0.f || t > 1.f)
     return false;
 

cc/trees/layer_sorter.h

@@ -11,10 +11,10 @@
 #include "base/containers/hash_tables.h"
 #include "cc/base/cc_export.h"
 #include "cc/layers/layer_impl.h"
-#include "ui/gfx/geometry/point3_f.h"
-#include "ui/gfx/geometry/quad_f.h"
-#include "ui/gfx/geometry/rect_f.h"
-#include "ui/gfx/geometry/vector3d_f.h"
+#include "ui/gfx/point3_f.h"
+#include "ui/gfx/quad_f.h"
+#include "ui/gfx/rect_f.h"
+#include "ui/gfx/vector3d_f.h"
 
 #if defined(COMPILER_GCC)
 namespace cc { struct GraphEdge; }