Provide approximate type functions for SkMatrix44.

ui/gfx/transform.h

Index: ui/gfx/transform.h
diff --git a/ui/gfx/transform.h b/ui/gfx/transform.h
index 60c3d5c3fa3acc0444d422c689c29538b487506c..362174182321053400e4b6d5441361b747d8c8f3 100644
--- a/ui/gfx/transform.h
+++ b/ui/gfx/transform.h
@@ -120,6 +120,10 @@ class GFX_EXPORT Transform {
     return !(matrix_.getType() & ~SkMatrix44::kTranslate_Mask);
   }
 
+  // Returns true if the matrix is either identity or pure translation,
+  // allowing for an amount of inaccuracy as specified by the parameter.
+  bool IsApproximatelyIdentityOrTranslation(SkMScalar tolerance) const;
+
   // Returns true if the matrix is either a positive scale and/or a translation.
   bool IsPositiveScaleOrTranslation() const {
     if (!IsScaleOrTranslation())