* Electron version: 1.6.2
* Operating system: macOS 10.12.3 (Sierra)

### Expected behavior

Scrollable elements should bounce (rubber band) when reaching the bounds if a window's `webPreferences.scrollBounce = true`

### Actual behavior

Bouncing does not happen

### How to reproduce

```javascript
var win = new BrowserWindow({
    width:800,
    height:600,
    webPreferences:{
        scrollBounce:true
    }
});
```

atom/renderer/renderer_client_base.cc
#include "base/strings/string_split.h"
#include "chrome/renderer/media/chrome_key_systems.h"
#include "chrome/renderer/pepper/pepper_helper.h"
#include "chrome/renderer/printing/print_web_view_helper.h"
#include "chrome/renderer/tts_dispatcher.h"
#include "content/public/common/content_constants.h"
#include "content/public/renderer/render_view.h"
#include "native_mate/dictionary.h"
#include "third_party/WebKit/public/web/WebCustomElement.h"
#include "third_party/WebKit/public/web/WebFrameWidget.h"
#include "third_party/WebKit/public/web/WebKit.h"
#include "third_party/WebKit/public/web/WebPluginParams.h"
#include "third_party/WebKit/public/web/WebSecurityPolicy.h"
#if defined(OS_MACOSX)
#include "base/mac/mac_util.h"
#include "base/strings/sys_string_conversions.h"
#endif
#if defined(OS_WIN)
#include <shlobj.h>
#endif
namespace atom {
namespace {
v8::Local<v8::Value> GetRenderProcessPreferences(
    const PreferencesManager* preferences_manager, v8::Isolate* isolate) {
  if (preferences_manager->preferences())
    return mate::ConvertToV8(isolate, *preferences_manager->preferences());
  else
    return v8::Null(isolate);
}
std::vector<std::string> ParseSchemesCLISwitch(const char* switch_name) {