CC: Allow cubic-bezier timing inputs outside the range [0, 1]

ui/gfx/geometry/cubic_bezier_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/geometry/cubic_bezier.h"
 
 #include "base/memory/scoped_ptr.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace gfx {
@@ skipping 146 matching lines @@
   EXPECT_NEAR(function.Slope(0.65), 1.26751, epsilon);
   EXPECT_NEAR(function.Slope(0.7), 1.21239, epsilon);
   EXPECT_NEAR(function.Slope(0.75), 1.13576, epsilon);
   EXPECT_NEAR(function.Slope(0.8), 1.03184, epsilon);
   EXPECT_NEAR(function.Slope(0.85), 0.89121, epsilon);
   EXPECT_NEAR(function.Slope(0.9), 0.69778, epsilon);
   EXPECT_NEAR(function.Slope(0.95), 0.42170, epsilon);
   EXPECT_NEAR(function.Slope(1), 0, epsilon);
 }
 
+TEST(CubicBezierTest, InputOutOfRange) {
+  CubicBezier simple(0.5, 1.0, 0.5, 1.0);
+  EXPECT_EQ(-2.0, simple.Solve(-1.0));
+  EXPECT_EQ(1.0, simple.Solve(2.0));
+
+  CubicBezier coincidentEndpoints(0.0, 0.0, 1.0, 1.0);
+  EXPECT_EQ(-1.0, coincidentEndpoints.Solve(-1.0));
+  EXPECT_EQ(2.0, coincidentEndpoints.Solve(2.0));

[Ian Vollick, 2015/01/05 15:36:04]

It'd be nice to have a test where one of the endpoints was coincident, but the
other wasn't. Also, having the first three knots coincident would be interesting
(0.0, 0.0, 0.0, 0.0).

[loyso (OOO), 2015/01/06 02:24:53]

As I mentioned above, this is a port of tests from here:
https://codereview.chromium.org/238573002

I agree, we should add this test. But to be consistent, we should add it on both
sides (cc/blink). I could setup a bug and introduce it as a separate CL.
What's the priority for that?

+
+  CubicBezier verticalGradient(0.0, 1.0, 1.0, 0.0);
+  EXPECT_EQ(0.0, verticalGradient.Solve(-1.0));
+  EXPECT_EQ(1.0, verticalGradient.Solve(2.0));
+
+  CubicBezier distinctEndpoints(0.1, 0.2, 0.8, 0.8);
+  EXPECT_EQ(-2.0, distinctEndpoints.Solve(-1.0));
+  EXPECT_EQ(2.0, distinctEndpoints.Solve(2.0));
+}
+
 }  // namespace
 }  // namespace gfx