[ast] Remove heap accesses from AST numbering

src/conversions.h

Index: src/conversions.h
diff --git a/src/conversions.h b/src/conversions.h
index 0472da89007eaebc0db108fcbc591dc55ee6bfd0..8cb8995253f68503cdf6eb0292e92835cd060e1b 100644
--- a/src/conversions.h
+++ b/src/conversions.h
@@ -167,6 +167,10 @@ inline bool IsInt32Double(double value);
 // We also have to check for negative 0 as it is not a UInteger32.
 inline bool IsUint32Double(double value);
 
+// Tries to convert |value| to uint32 -- if it fails, returns false; otherwise,
+// sets |uint32_value| to the integer value and returns true.
+inline bool DoubleToUint32(double value, uint32_t* uint32_value);
+
 // Convert from Number object to C integer.
 inline uint32_t PositiveNumberToUint32(Object* number);
 inline int32_t NumberToInt32(Object* number);