Decouple root visitors from object visitors.

src/interpreter/interpreter.h

Index: src/interpreter/interpreter.h
diff --git a/src/interpreter/interpreter.h b/src/interpreter/interpreter.h
index 4dc6241c245f3e710e874c9e094b2f93cb12b207..2df29bee4199036148cb75cd011404eb4b226987 100644
--- a/src/interpreter/interpreter.h
+++ b/src/interpreter/interpreter.h
@@ -24,6 +24,7 @@ class Callable;
 class CompilationInfo;
 class CompilationJob;
 class SetupIsolateDelegate;
+class RootVisitor;
 
 namespace interpreter {
 
@@ -44,7 +45,7 @@ class Interpreter {
   Code* GetBytecodeHandler(Bytecode bytecode, OperandScale operand_scale);
 
   // GC support.
-  void IterateDispatchTable(ObjectVisitor* v);
+  void IterateDispatchTable(RootVisitor* v);
 
   // Disassembler support (only useful with ENABLE_DISASSEMBLER defined).
   const char* LookupNameOfBytecodeHandler(Code* code);