Move gc notifications from V8 to Isolate and make idle hint mandatory

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index 46d4fc96d3ba1304a9f71f24419d0c520044fe8d..6d656430bc17303ec99f3b86e0687b4f99d72471 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -4459,6 +4459,34 @@ class V8_EXPORT Isolate {
   void SetCreateHistogramFunction(CreateHistogramCallback);
   void SetAddHistogramSampleFunction(AddHistogramSampleCallback);
 
+  /**
+   * Optional notification that the embedder is idle.
+   * V8 uses the notification to reduce memory footprint.
+   * This call can be used repeatedly if the embedder remains idle.
+   * Returns true if the embedder should stop calling IdleNotification
+   * until real work has been done.  This indicates that V8 has done
+   * as much cleanup as it will be able to do.
+   *
+   * The idle_time_in_ms argument specifies the time V8 has to do reduce
+   * the memory footprint. There is no guarantee that the actual work will be
+   * done within the time limit.
+   */
+  bool IdleNotification(int idle_time_in_ms);
+
+  /**
+   * Optional notification that the system is running low on memory.
+   * V8 uses these notifications to attempt to free memory.
+   */
+  void LowMemoryNotification();
+
+  /**
+   * Optional notification that a context has been disposed. V8 uses
+   * these notifications to guide the GC heuristic. Returns the number
+   * of context disposals - including this one - since the last time
+   * V8 had a chance to clean up.
+   */
+  int ContextDisposedNotification();
+
  private:
   template<class K, class V, class Traits> friend class PersistentValueMap;
 
@@ -4969,12 +4997,16 @@ class V8_EXPORT V8 {
    * The hint argument specifies the amount of work to be done in the function
    * on scale from 1 to 1000. There is no guarantee that the actual work will
    * match the hint.
+   *
+   * Deprecated, please use Isolate::IdleNotification.
    */
   static bool IdleNotification(int hint = 1000);
 
   /**
    * Optional notification that the system is running low on memory.
    * V8 uses these notifications to attempt to free memory.
+   *
+   * Deprecated, please use Isolate::LowMemoryNotification.
    */
   static void LowMemoryNotification();
 
@@ -4983,6 +5015,8 @@ class V8_EXPORT V8 {
    * these notifications to guide the GC heuristic. Returns the number
    * of context disposals - including this one - since the last time
    * V8 had a chance to clean up.
+   *
+   * Deprecated, please use Isolate::ContextDisposedNotification.
    */
   static int ContextDisposedNotification();