- Implement a first cut for const String.env in the VM to allow

runtime/vm/isolate.h

 // Copyright (c) 2013, 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.
 
 #ifndef VM_ISOLATE_H_
 #define VM_ISOLATE_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/thread.h"
@@ skipping 156 matching lines @@
     return OFFSET_OF(Isolate, current_zone_);
   }
 
   void set_init_callback_data(void* value) {
     init_callback_data_ = value;
   }
   void* init_callback_data() const {
     return init_callback_data_;
   }
 
+  Dart_EnvironmentCallback environment_callback() const {
+    return environment_callback_;
+  }
+  void set_environment_callback(Dart_EnvironmentCallback value) {
+    environment_callback_ = value;
+  }
+
   Dart_LibraryTagHandler library_tag_handler() const {
     return library_tag_handler_;
   }
   void set_library_tag_handler(Dart_LibraryTagHandler value) {
     library_tag_handler_ = value;
   }
 
   void SetStackLimit(uword value);
   void SetStackLimitFromCurrentTOS(uword isolate_stack_top);
 
@@ skipping 199 matching lines @@
   MegamorphicCacheTable megamorphic_cache_table_;
   Dart_MessageNotifyCallback message_notify_callback_;
   char* name_;
   int64_t start_time_;
   Dart_Port main_port_;
   Heap* heap_;
   ObjectStore* object_store_;
   RawContext* top_context_;
   uword top_exit_frame_info_;
   void* init_callback_data_;
+  Dart_EnvironmentCallback environment_callback_;
   Dart_LibraryTagHandler library_tag_handler_;
   ApiState* api_state_;
   StubCode* stub_code_;
   Debugger* debugger_;
   bool single_step_;
   Simulator* simulator_;
   LongJump* long_jump_base_;
   TimerList timer_list_;
   intptr_t deopt_id_;
   Mutex* mutex_;  // protects stack_limit_ and saved_stack_limit_.
@@ skipping 124 matching lines @@
   Isolate* isolate_;
   char* script_url_;
   char* library_url_;
   char* function_name_;
   char* exception_callback_name_;
 };
 
 }  // namespace dart
 
 #endif  // VM_ISOLATE_H_