Add JSRESOLVE_DECLARING and JSRESOLVE_CLASSNAME support for better DOM quirk emulation (257602, r=shaver).

js/src/jsopcode.h

@@ -92,6 +92,7 @@ typedef enum JSOp {
 #define JOF_DETECTING     0x2000  /* object detection flag for JSNewResolveOp */
 #define JOF_BACKPATCH     0x4000  /* backpatch placeholder during codegen */
 #define JOF_LEFTASSOC     0x8000  /* left-associative operator */
+#define JOF_DECLARING    0x10000  /* var, const, or function declaration op */
 
 #define JOF_TYPE_IS_EXTENDED_JUMP(t) \
     ((unsigned)((t) - JOF_JUMPX) <= (unsigned)(JOF_LOOKUPSWITCHX - JOF_JUMPX))