Add dead CodeRegionTable for tracking overwritten Dart code

runtime/bin/vmservice/client/lib/src/service/cache.dart

Index: runtime/bin/vmservice/client/lib/src/service/cache.dart
diff --git a/runtime/bin/vmservice/client/lib/src/service/cache.dart b/runtime/bin/vmservice/client/lib/src/service/cache.dart
index 02604ce9915599aa50a2dc91f657fdf68b5bd999..28b07ee6127a4c43043564d00babb9ed38ab667a 100644
--- a/runtime/bin/vmservice/client/lib/src/service/cache.dart
+++ b/runtime/bin/vmservice/client/lib/src/service/cache.dart
@@ -117,11 +117,11 @@ class CodeCache extends ServiceObjectCache<Code> {
   }
 
   void _updateProfileData(ServiceMap profile, List<Code> codeTable) {
-    var codes = profile['codes'];
+    var codeRegions = profile['codes'];
     var sampleCount = profile['samples'];
-    for (var profileCode in codes) {
-      Code code = profileCode['code'];
-      code.updateProfileData(profileCode, codeTable, sampleCount);
+    for (var codeRegion in codeRegions) {
+      Code code = codeRegion['code'];
+      code.updateProfileData(codeRegion, codeTable, sampleCount);
     }
   }
 }