Address review comments for r39595.

runtime/vm/flow_graph_range_analysis.h

Index: runtime/vm/flow_graph_range_analysis.h
diff --git a/runtime/vm/flow_graph_range_analysis.h b/runtime/vm/flow_graph_range_analysis.h
index d81538550f3faef723338099720a92430ddd07e3..fa07e6037826d31a0915fa74e35026a9d06e51f5 100644
--- a/runtime/vm/flow_graph_range_analysis.h
+++ b/runtime/vm/flow_graph_range_analysis.h
@@ -425,10 +425,6 @@ class Range : public ZoneAllocated {
            !max().UpperBound().Overflowed(size);
   }
 
-  static bool Fits(Range* range, RangeBoundary::RangeSize size) {
-    return !IsUnknown(range) && range->Fits(size);
-  }
-
   // Clamp this to be within size.
   void Clamp(RangeBoundary::RangeSize size);
 
@@ -485,6 +481,18 @@ class Range : public ZoneAllocated {
 };
 
 
+class RangeUtils : public AllStatic  {
+ public:
+  static bool Fits(Range* range, RangeBoundary::RangeSize size) {
+    return !Range::IsUnknown(range) && range->Fits(size);
+  }
+
+  static bool IsWithin(Range* range, int64_t min, int64_t max) {
+    return !Range::IsUnknown(range) && range->IsWithin(min, max);
+  }
+};
+
+
 // Range analysis for integer values.
 class RangeAnalysis : public ValueObject {
  public: