Initial isolate reload support

runtime/vm/snapshot.h

Index: runtime/vm/snapshot.h
diff --git a/runtime/vm/snapshot.h b/runtime/vm/snapshot.h
index 8b540f38bebfdd3727e1dd76c2b2c0535d2143f1..5baf16af2bb52c96a7e490ea0bc4b2439f174d50 100644
--- a/runtime/vm/snapshot.h
+++ b/runtime/vm/snapshot.h
@@ -410,6 +410,7 @@ class SnapshotReader : public BaseReader {
   ClassTable* class_table() const { return isolate()->class_table(); }
   PassiveObject* PassiveObjectHandle() { return &pobj_; }
   Array* ArrayHandle() { return &array_; }
+  Class* ClassHandle() { return &cls_; }
   String* StringHandle() { return &str_; }
   AbstractType* TypeHandle() { return &type_; }
   TypeArguments* TypeArgumentsHandle() { return &type_arguments_; }
@@ -1104,7 +1105,6 @@ class SnapshotWriter : public BaseWriter {
   friend class RawGrowableObjectArray;
   friend class RawImmutableArray;
   friend class RawInstructions;
-  friend class RawRegExp;
   friend class RawLibrary;
   friend class RawLinkedHashMap;
   friend class RawLiteralToken;
@@ -1112,11 +1112,14 @@ class SnapshotWriter : public BaseWriter {
   friend class RawMirrorReference;
   friend class RawObjectPool;
   friend class RawReceivePort;
+  friend class RawRegExp;
   friend class RawScript;
   friend class RawStacktrace;
   friend class RawSubtypeTestCache;
   friend class RawTokenStream;
+  friend class RawType;
   friend class RawTypeArguments;
+  friend class RawTypeParameter;
   friend class RawUserTag;
   friend class SnapshotWriterVisitor;
   friend class WriteInlinedObjectVisitor;