* Electron version: 1.6.7
* Operating system: Mac OS X 10.10.5 and Windows 8.1

I realize 1.6.7 is still in beta but thought I should report a memory leak I am seeing...  in a simple app that does window.open with every new window opened the memory keeps growing and is never released when the sub-windows get closed.

The demo repo is committed here: https://github.com/lneir/electron-memory-leak

To repo.
1. git clone https://github.com/lneir/electron-memory-leak.git
2. npm i
3. npm run start
4. in the main window click the open window button 5 times.
Notice: the memory goes very high (approx 500 Mbytes) because each sub-window is allocating a big chunk of memory.
5. now close all the open windows.

Result: the memory of the renderer process stays very high
Expected: memory to go back to original before all sub-windows were opened.

Note: This does not happen on electron 1.4.16 but only appears to be a problem in electron 1.6.7.  
Note: Also the problem seems to be related to the having preload enabled

atom/common/api/object_life_monitor.h
#ifndef ATOM_COMMON_API_OBJECT_LIFE_MONITOR_H_
#define ATOM_COMMON_API_OBJECT_LIFE_MONITOR_H_
#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "v8/include/v8.h"
namespace atom {
class ObjectLifeMonitor {
 protected:
  ObjectLifeMonitor(v8::Isolate* isolate, v8::Local<v8::Object> target);
  virtual ~ObjectLifeMonitor();
  virtual void RunDestructor() = 0;
 private:
  static void OnObjectGC(const v8::WeakCallbackInfo<ObjectLifeMonitor>& data);
  static void Free(const v8::WeakCallbackInfo<ObjectLifeMonitor>& data);
  v8::Global<v8::Context> context_;
  v8::Global<v8::Object> target_;
  base::WeakPtrFactory<ObjectLifeMonitor> weak_ptr_factory_;
  DISALLOW_COPY_AND_ASSIGN(ObjectLifeMonitor);
};
}  
#endif