[heap, debugger] Introduce out-of-memory listener for debugger.

src/debug/debug-interface.h

Index: src/debug/debug-interface.h
diff --git a/src/debug/debug-interface.h b/src/debug/debug-interface.h
index b5c7dab516cd2645c905231dc378c80958025d00..b4216d7a54106dfd7ba24d0aa4f32e33a1f81686 100644
--- a/src/debug/debug-interface.h
+++ b/src/debug/debug-interface.h
@@ -139,6 +139,16 @@ void PrepareStep(Isolate* isolate, StepAction action);
 void ClearStepping(Isolate* isolate);
 
 /**
+ * Out-of-memory callback function.
+ * The function is invoked when the heap size is close to the hard limit.
+ *
+ * \param data the parameter provided during callback installation.
+ */
+typedef void (*OutOfMemoryCallback)(void* data);
+void SetOutOfMemoryCallback(Isolate* isolate, OutOfMemoryCallback callback,
+                            void* data);
+
+/**
  * Native wrapper around v8::internal::Script object.
  */
 class Script {