Remove GC prologue and epilogue callbacks.

runtime/include/dart_api.h

Index: runtime/include/dart_api.h
diff --git a/runtime/include/dart_api.h b/runtime/include/dart_api.h
index 9b4447797d1e31e2ebef9990b93a45095562220c..e3e548360ffae60c4c374e325194af6327408c14 100644
--- a/runtime/include/dart_api.h
+++ b/runtime/include/dart_api.h
@@ -517,49 +517,6 @@ DART_EXPORT void Dart_DeleteWeakPersistentHandle(
     Dart_Isolate isolate,
     Dart_WeakPersistentHandle object);
 
-/*
- * ============================
- * Garbage Collection Callbacks
- * ============================
- */
-
-/**
- * Callbacks signal the beginning and end of a garbage collection.
- *
- * These signals are intended to be used by the embedder to manage the
- * lifetime of native objects with a managed object peer.
- */
-
-/**
- * A callback invoked at the beginning of a garbage collection.
- */
-typedef void (*Dart_GcPrologueCallback)();
-
-/**
- * A callback invoked at the end of a garbage collection.
- */
-typedef void (*Dart_GcEpilogueCallback)();
-
-/**
- * Adds garbage collection callbacks (prologue and epilogue).
- *
- * \param prologue_callback A function pointer to a prologue callback function.
- *   A prologue callback function should not be already set when this function
- *   is called. A NULL value removes the existing prologue callback function
- *   if any.
- *
- * \param epilogue_callback A function pointer to an epilogue callback function.
- *   An epilogue callback function should not be already set when this function
- *   is called. A NULL value removes the existing epilogue callback function
- *   if any.
- *
- * \return Success if the callbacks were added.  Otherwise, returns an
- *   error handle.
- */
-DART_EXPORT Dart_Handle
-Dart_SetGcCallbacks(Dart_GcPrologueCallback prologue_callback,
-                    Dart_GcEpilogueCallback epilogue_callback);
-
 /*
  * ==========================
  * Initialization and Globals