Remove the ability to allow multiple gc prologue and gc epilogue callbacks

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"
 #include "vm/base_isolate.h"
 #include "vm/class_table.h"
-#include "vm/gc_callbacks.h"
 #include "vm/handles.h"
 #include "vm/megamorphic_cache_table.h"
 #include "vm/random.h"
 #include "vm/store_buffer.h"
 #include "vm/timer.h"
 
 namespace dart {
 
 // Forward declarations.
 class AbstractType;
@@ skipping 275 matching lines @@
   bool single_step() const { return single_step_; }
   static intptr_t single_step_offset() {
     return OFFSET_OF(Isolate, single_step_);
   }
 
   Random* random() { return &random_; }
 
   Simulator* simulator() const { return simulator_; }
   void set_simulator(Simulator* value) { simulator_ = value; }
 
-  GcPrologueCallbacks& gc_prologue_callbacks() {
-    return gc_prologue_callbacks_;
+  Dart_GcPrologueCallback gc_prologue_callback() const {
+    return gc_prologue_callback_;
   }
 
-  GcEpilogueCallbacks& gc_epilogue_callbacks() {
-    return gc_epilogue_callbacks_;
+  void set_gc_prologue_callback(Dart_GcPrologueCallback callback) {
+    gc_prologue_callback_ = callback;
+  }
+
+  Dart_GcEpilogueCallback gc_epilogue_callback() const {
+    return gc_epilogue_callback_;
+  }
+
+  void set_gc_epilogue_callback(Dart_GcEpilogueCallback callback) {
+    gc_epilogue_callback_ = callback;
   }
 
   static void SetCreateCallback(Dart_IsolateCreateCallback cb) {
     create_callback_ = cb;
   }
   static Dart_IsolateCreateCallback CreateCallback() {
     return create_callback_;
   }
 
   static void SetServiceCreateCallback(Dart_ServiceIsolateCreateCalback cb) {
@@ skipping 167 matching lines @@
   Simulator* simulator_;
   LongJumpScope* long_jump_base_;
   TimerList timer_list_;
   intptr_t deopt_id_;
   Mutex* mutex_;  // protects stack_limit_ and saved_stack_limit_.
   uword stack_limit_;
   uword saved_stack_limit_;
   MessageHandler* message_handler_;
   IsolateSpawnState* spawn_state_;
   bool is_runnable_;
-  GcPrologueCallbacks gc_prologue_callbacks_;
-  GcEpilogueCallbacks gc_epilogue_callbacks_;
+  Dart_GcPrologueCallback gc_prologue_callback_;
+  Dart_GcEpilogueCallback gc_epilogue_callback_;
   intptr_t defer_finalization_count_;
   DeoptContext* deopt_context_;
 
   // Status support.
   char* stacktrace_;
   intptr_t stack_frame_index_;
 
   bool cha_used_;
 
   // Ring buffer of objects assigned an id.
@@ skipping 137 matching lines @@
   char* script_url_;
   char* library_url_;
   char* class_name_;
   char* function_name_;
   char* exception_callback_name_;
 };
 
 }  // namespace dart
 
 #endif  // VM_ISOLATE_H_