cc: Use SkMScalar instead of doubles everywhere in cc

cc/base/math_util.h

Index: cc/base/math_util.h
diff --git a/cc/base/math_util.h b/cc/base/math_util.h
index 6cf929c16f749215699c6d8a591e0f1b8ea273a1..7912f8a8a252a11b409cc9b0c19a2fbba7e6ccbd 100644
--- a/cc/base/math_util.h
+++ b/cc/base/math_util.h
@@ -45,7 +45,7 @@ struct HomogeneousCoordinate {
     // For now, because this code is used privately only by MathUtil, it should
     // never be called when w == 0, and we do not yet need to handle that case.
     DCHECK(w());
-    double inv_w = 1.0 / w();
+    SkMScalar inv_w = 1.0 / w();
     return gfx::PointF(x() * inv_w, y() * inv_w);
   }
 
@@ -56,7 +56,7 @@ struct HomogeneousCoordinate {
     // For now, because this code is used privately only by MathUtil, it should
     // never be called when w == 0, and we do not yet need to handle that case.
     DCHECK(w());
-    double inv_w = 1.0 / w();
+    SkMScalar inv_w = 1.0 / w();
     return gfx::Point3F(x() * inv_w, y() * inv_w, z() * inv_w);
   }