Remove unnecessary isolate argument from some visitors

runtime/vm/snapshot.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/snapshot.h"
 
 #include "platform/assert.h"
 #include "vm/bootstrap.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart.h"
@@ skipping 1827 matching lines @@
 #undef VM_OBJECT_WRITE
 
 
 // An object visitor which will iterate over all the script objects in the heap
 // and either count them or collect them into an array. This is used during
 // full snapshot generation of the VM isolate to write out all script
 // objects and their accompanying token streams.
 class ScriptVisitor : public ObjectVisitor {
  public:
   explicit ScriptVisitor(Thread* thread) :
-      ObjectVisitor(thread->isolate()),
       objHandle_(Object::Handle(thread->zone())),
       count_(0),
       scripts_(NULL) {}
 
   ScriptVisitor(Thread* thread, const Array* scripts) :
-      ObjectVisitor(thread->isolate()),
       objHandle_(Object::Handle(thread->zone())),
       count_(0),
       scripts_(scripts) {}
 
   void VisitObject(RawObject* obj) {
     if (obj->IsScript()) {
       if (scripts_ != NULL) {
         objHandle_ = obj;
         scripts_->SetAt(count_, objHandle_);
       }
@@ skipping 399 matching lines @@
   }
 
   const Object& obj = Object::Handle(raw);
   FATAL1("Unexpected object: %s\n", obj.ToCString());
 }
 
 
 class WriteInlinedObjectVisitor : public ObjectVisitor {
  public:
   explicit WriteInlinedObjectVisitor(SnapshotWriter* writer)
-      : ObjectVisitor(Isolate::Current()), writer_(writer) {}
+      : writer_(writer) {}
 
   virtual void VisitObject(RawObject* obj) {
     intptr_t object_id = writer_->forward_list_->FindObject(obj);
     ASSERT(object_id != kInvalidIndex);
     intptr_t tags = writer_->GetObjectTags(obj);
     writer_->WriteMarkedObjectImpl(obj, tags, object_id, kAsInlinedObject);
   }
 
  private:
   SnapshotWriter* writer_;
@@ skipping 377 matching lines @@
   if (setjmp(*jump.Set()) == 0) {
     NoSafepointScope no_safepoint;
     WriteObject(obj.raw());
   } else {
     ThrowException(exception_type(), exception_msg());
   }
 }
 
 
 }  // namespace dart