Don't add duplicate points when clipping

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 05014ee5c19dffd7abb676c8ba0a3f5e7e90753e..0398bb683feef2f1a67f936e99e2fa184ea7ee77 100644
--- a/cc/base/math_util.h
+++ b/cc/base/math_util.h
@@ -335,6 +335,10 @@ class ScopedSubnormalFloatDisabler {
   DISALLOW_COPY_AND_ASSIGN(ScopedSubnormalFloatDisabler);
 };
 
+bool IsApproximatelyForUnitTesting(const float left, const float right);
+bool IsApproximatelyForUnitTesting(const gfx::PointF& l, const gfx::PointF& r);
+bool IsApproximatelyForUnitTesting(const gfx::Point3F& l,
+                                   const gfx::Point3F& r);
 }  // namespace cc
 
 #endif  // CC_BASE_MATH_UTIL_H_