Add memory pressure interrupt for memory pressure notification

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index 62319203f418c4522b103b3d54ced4e43f09971b..bfabad156c628e0413bb4b709e9e2084190d44a9 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -5554,6 +5554,8 @@ class V8_EXPORT Isolate {
     kUseCounterFeatureCount  // This enum value must be last.
   };
 
+  enum MemoryPressureLevel { kNone, kModerate, kCritical };

[jochen (gone - plz use gerrit), 2016/03/15 20:57:18]

this should be an enum class

+
   typedef void (*UseCounterCallback)(Isolate* isolate,
                                      UseCounterFeature feature);
 
@@ -5875,6 +5877,12 @@ class V8_EXPORT Isolate {
   void RequestInterrupt(InterruptCallback callback, void* data);
 
   /**
+   * Request V8 to interrupt long running JavaScript code and do GC,
+   * when system memory is pressured.
+   */
+  void RequestMemoryPressureInterrupt(MemoryPressureLevel level);

[jochen (gone - plz use gerrit), 2016/03/15 20:57:18]

this should be NotifyMemoryPressure(MemoryPressureLevel)

+
+  /**
    * Request garbage collection in this Isolate. It is only valid to call this
    * function if --expose_gc was specified.
    *
@@ -6185,6 +6193,12 @@ class V8_EXPORT Isolate {
    */
   void VisitWeakHandles(PersistentHandleVisitor* visitor);
 
+  /**
+   * This method can handle memory pressure interrupt, no matter v8 is busy or
+   * idle.
+   */
+  void HandleMemoryPressureInterrupt();

[jochen (gone - plz use gerrit), 2016/03/15 20:57:18]

please remove this.

+
  private:
   template <class K, class V, class Traits>
   friend class PersistentValueMapBase;