Bug 1164557 - Use COORDINATE_EPSILON in IsZero(). r=kats

--HG--
extra : source : fe7548a3554a7d6033147f616612005a8242f7a0

gfx/layers/apz/src/APZUtils.h

@@ -38,11 +38,19 @@ enum class ScrollSource {
 
 typedef uint32_t TouchBehaviorFlags;
 
+// Epsilon to be used when comparing 'float' coordinate values
+// with FuzzyEqualsAdditive. The rationale is that 'float' has 7 decimal
+// digits of precision, and coordinate values should be no larger than in the
+// ten thousands. Note also that the smallest legitimate difference in page
+// coordinates is 1 app unit, which is 1/60 of a (CSS pixel), so this epsilon
+// isn't too large.
+const float COORDINATE_EPSILON = 0.01f;
+
 template <typename Units>
 static bool IsZero(const gfx::PointTyped<Units>& aPoint)
 {
-  return FuzzyEqualsAdditive(aPoint.x, 0.0f)
-      && FuzzyEqualsAdditive(aPoint.y, 0.0f);
+  return FuzzyEqualsAdditive(aPoint.x, 0.0f, COORDINATE_EPSILON)
+      && FuzzyEqualsAdditive(aPoint.y, 0.0f, COORDINATE_EPSILON);
 }
 
 }

gfx/layers/apz/src/Axis.h

@@ -8,6 +8,7 @@
 #define mozilla_layers_Axis_h
 
 #include <sys/types.h>                  // for int32_t
+#include "APZUtils.h"
 #include "Units.h"
 #include "mozilla/TimeStamp.h"          // for TimeDuration
 #include "nsTArray.h"                   // for nsTArray
@@ -17,14 +18,6 @@ namespace layers {
 
 const float EPSILON = 0.0001f;
 
-// Epsilon to be used when comparing 'float' coordinate values
-// with FuzzyEqualsAdditive. The rationale is that 'float' has 7 decimal
-// digits of precision, and coordinate values should be no larger than in the
-// ten thousands. Note also that the smallest legitimate difference in page
-// coordinates is 1 app unit, which is 1/60 of a (CSS pixel), so this epsilon
-// isn't too large.
-const float COORDINATE_EPSILON = 0.01f;
-
 /**
  * Compare two coordinates for equality, accounting for rounding error.
  * Use both FuzzyEqualsAdditive() with COORDINATE_EPISLON, which accounts for