Provide approximate type functions for SkMatrix44.

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 67a93709d0fe57efdc9d90d89466a665d268f4b6..0123eb468d3cd8a7d927f86b4554f079e13e731d 100644
--- a/cc/base/math_util.h
+++ b/cc/base/math_util.h
@@ -177,6 +177,18 @@ class CC_EXPORT MathUtil {
   // If the value is inf, returns max double/float representation.
   static scoped_ptr<base::Value> AsValueSafely(double value);
   static scoped_ptr<base::Value> AsValueSafely(float value);
+
+  // Check if matrices are of a certain type using approximate math. Each
+  // function gets a tolerance parameter to specify the maximum allowed
+  // absolute difference to the exact values.
+  static bool IsApproximatelyPureTranslation(
+      const gfx::Transform& transform, SkMScalar tolerance);
+  static bool IsMatrixApproximatelyPureTranslation(
+      const SkMatrix44& matrix, SkMScalar tolerance);
+  static bool IsApproximatelyIntegerTransform(
+      const gfx::Transform& transform, SkMScalar tolerance);
+  static bool IsMatrixApproximatelyIntegerTransform(
+      const SkMatrix44& matrix, SkMScalar tolerance);
 };
 
 }  // namespace cc