Revert "Hide Isolate pointer from embedder"

runtime/vm/debugger_api_impl.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 "include/dart_debugger_api.h"
 
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_api_state.h"
@@ skipping 958 matching lines @@
   if (lib.IsNull()) {
     return Api::NewError("%s: %" Pd " is not a valid library id",
                          CURRENT_FUNC, library_id);
   }
   lib.set_debuggable(is_debuggable);
   return Api::Success();
 }
 
 
 DART_EXPORT Dart_Isolate Dart_GetIsolate(Dart_IsolateId isolate_id) {
-  // Dart_Isolate is now the same as Dart_IsolateId.
-  // TODO(johnmccutchan): Kill Dart_IsolateId.
-  return static_cast<Dart_Isolate>(isolate_id);
+  Isolate* isolate = PortMap::GetIsolate(isolate_id);
+  return Api::CastIsolate(isolate);
 }
 
 
 DART_EXPORT Dart_IsolateId Dart_GetIsolateId(Dart_Isolate dart_isolate) {
-  // Dart_Isolate is now the same as Dart_IsolateId.
-  // TODO(johnmccutchan): Kill Dart_IsolateId.
-  return static_cast<Dart_IsolateId>(dart_isolate);
+  Isolate* isolate = reinterpret_cast<Isolate*>(dart_isolate);
+  return isolate->debugger()->GetIsolateId();
 }
 
 }  // namespace dart