Fix matrix interpolation between rotations of 180 degrees

ui/gfx/transform_unittest.cc

Index: ui/gfx/transform_unittest.cc
diff --git a/ui/gfx/transform_unittest.cc b/ui/gfx/transform_unittest.cc
index b1b880af0e01cd75d5046d87dc7e3f8412f70730..9824f2c9d9186b27ec6dea6e8339c9858d3b9c47 100644
--- a/ui/gfx/transform_unittest.cc
+++ b/ui/gfx/transform_unittest.cc
@@ -745,8 +745,13 @@ TEST(XFormTest, CanBlend180DegreeRotation) {
       // A 180 degree rotation is exactly opposite on the sphere, therefore
       // either great circle arc to it is equivalent (and numerical precision
       // will determine which is closer).  Test both directions.
-      Transform expected = from;
-      EXPECT_TRUE(MatricesAreNearlyEqual(expected, to))
+      Transform expected1;
+      expected1.RotateAbout(axes[index], 180.0 * t);
+      Transform expected2;
+      expected2.RotateAbout(axes[index], -180.0 * t);
+
+      EXPECT_TRUE(MatricesAreNearlyEqual(expected1, to) ||
+                  MatricesAreNearlyEqual(expected2, to))
           << "axis: " << index << ", i: " << i;
     }
   }