color: Do not enforce T(0)=0 and T(1)=1 constraints in approxmation

ui/gfx/color_space_unittest.cc

Index: ui/gfx/color_space_unittest.cc
diff --git a/ui/gfx/color_space_unittest.cc b/ui/gfx/color_space_unittest.cc
index c9c8775ccce721ab86fe6bf9a9a66f7f7ef172eb..c80fbb8aa903cd88a3cc5c24974091bf66a2ce6e 100644
--- a/ui/gfx/color_space_unittest.cc
+++ b/ui/gfx/color_space_unittest.cc
@@ -109,8 +109,8 @@ TEST_P(ColorSpaceTableTest, ApproximateTransferFn) {
 
   for (size_t i = 0; i < x.size(); ++i) {
     float fn_approx_of_x = SkTransferFnEval(fn_approx, x[i]);
-    EXPECT_NEAR(t[i], fn_approx_of_x, 2.f / 256.f);
-    if (std::abs(t[i] - fn_approx_of_x) > 2.f / 256.f)
+    EXPECT_NEAR(t[i], fn_approx_of_x, 3.f / 256.f);
+    if (std::abs(t[i] - fn_approx_of_x) > 3.f / 256.f)
       break;
   }
 }