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

runtime/vm/gc_callbacks.h

Index: runtime/vm/gc_callbacks.h
===================================================================
--- runtime/vm/gc_callbacks.h	(revision 33620)
+++ runtime/vm/gc_callbacks.h	(working copy)
@@ -1,111 +0,0 @@
-// 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.
-
-#ifndef VM_GC_CALLBACKS_H_
-#define VM_GC_CALLBACKS_H_
-
-#include "include/dart_api.h"
-#include "platform/utils.h"
-
-namespace dart {
-
-// A container for garbage collection callback function pointers.
-// Pointers to the callback methods are stored within linked list
-// nodes managed by the container.
-template<typename T>
-class GcCallbacks {
- public:
-  GcCallbacks() : head_(NULL) {
-  }
-
-  ~GcCallbacks() {
-    while (head_ != NULL) {
-      Link* prev = head_;
-      head_ = head_->next_;
-      delete prev;
-    }
-  }
-
-  // Adds a new callback to the list.  The new callback must not
-  // already be present in the list.
-  void Add(T callback) {
-    ASSERT(callback != NULL);
-    Link* link = new Link(callback, head_);
-    head_ = link;
-  }
-
-  // Removes a callback from the list.  The callback must be present
-  // in the list.
-  void Remove(T callback) {
-    ASSERT(callback != NULL);
-    if (head_ == NULL) return;
-    Link* prev = head_;
-    Link* curr = head_->next_;
-    if (prev->callback_ == callback) {
-      head_ = curr;
-      delete prev;
-      return;
-    }
-    while (curr != NULL) {
-      if (curr->callback_ == callback) {
-        prev->next_ = curr->next_;
-        delete curr;
-        return;
-      }
-      prev = curr;
-      curr = curr->next_;
-    }
-  }
-
-  // Iterates through all of the callbacks in the list and invokes
-  // their callback methods.
-  void Invoke() const {
-    for (Link* curr = head_; curr != NULL; curr = curr->next_) {
-      (*curr->callback_)();
-    }
-  }
-
-  // Returns the number of callbacks stored in the list.
-  intptr_t Count() const {
-    intptr_t sum = 0;
-    for (Link* curr = head_; curr != NULL; curr = curr->next_) {
-      ++sum;
-    }
-    return sum;
-  }
-
-  // Returns true if the specified callback is present in the
-  // container.
-  bool Contains(T callback) const {
-    for (Link* curr = head_; curr != NULL; curr = curr->next_) {
-      if (curr->callback_ == callback) {
-        return true;
-      }
-    }
-    return false;
-  }
-
- private:
-  // A linked-list element.
-  struct Link {
-    Link(T callback, Link* next) : callback_(callback), next_(next) {
-    }
-    T callback_;
-    Link* next_;
-  };
-
-  Link* head_;
-};
-
-
-// A container for storing garbage collection prologue methods.
-class GcPrologueCallbacks : public GcCallbacks<Dart_GcPrologueCallback> {};
-
-
-// A container for storing garbage collection epilogue methods.
-class GcEpilogueCallbacks : public GcCallbacks<Dart_GcEpilogueCallback> {};
-
-};  // namespace dart
-
-#endif  // VM_GC_CALLBACKS_H_