Add memory pressure interrupt for memory pressure notification

include/v8.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /** \mainpage V8 API Reference Guide
  *
  * V8 is Google's open source JavaScript engine.
  *
  * This set of documents provides reference material generated from the
  * V8 header file, include/v8.h.
@@ skipping 5536 matching lines @@
     kArrayInstanceConstructorModified = 28,
     kLegacyFunctionDeclaration = 29,
     kRegExpPrototypeSourceGetter = 30,
     kRegExpPrototypeOldFlagGetter = 31,
 
     // If you add new values here, you'll also need to update V8Initializer.cpp
     // in Chromium.
     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);
 
 
   /**
    * Creates a new isolate.  Does not change the currently entered
    * isolate.
    *
    * When an isolate is no longer used its resources should be freed
    * by calling Dispose().  Using the delete operator is not allowed.
@@ skipping 301 matching lines @@
    * Request V8 to interrupt long running JavaScript code and invoke
    * the given |callback| passing the given |data| to it. After |callback|
    * returns control will be returned to the JavaScript code.
    * There may be a number of interrupt requests in flight.
    * Can be called from another thread without acquiring a |Locker|.
    * Registered |callback| must not reenter interrupted 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.
    *
    * This should only be used for testing purposes and not to enforce a garbage
    * collection schedule. It has strong negative impact on the garbage
    * collection performance. Use IdleNotificationDeadline() or
    * LowMemoryNotification() instead to influence the garbage collection
    * schedule.
    */
   void RequestGarbageCollectionForTesting(GarbageCollectionType type);
@@ skipping 290 matching lines @@
    */
   void VisitHandlesForPartialDependence(PersistentHandleVisitor* visitor);
 
   /**
    * Iterates through all the persistent handles in the current isolate's heap
    * that have class_ids and are weak to be marked as inactive if there is no
    * pending activity for the handle.
    */
   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;
 
   Isolate();
   Isolate(const Isolate&);
   ~Isolate();
   Isolate& operator=(const Isolate&);
   void* operator new(size_t size);
   void operator delete(void*, size_t);
@@ skipping 2460 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // INCLUDE_V8_H_