### Issue Details

* **Electron Version:**
  * `8.3.3`
* **Operating System:**
  * Windows 10 2004
* **Last Known Working Electron version:**
  * `7.x`

### Expected Behavior
You can write and read from clipboard via `Buffer`.

### Actual Behavior
You can write but not read.

### To Reproduce

```js
setTimeout(() => {
  clipboard.writeBuffer('code/file-list', Buffer.from("Hello World"));
  console.log("did write")
}, 1000);

setTimeout(() => {
  const res = clipboard.readBuffer('code/file-list');
  console.log(res.toString());
}, 2000);
```

The output is empty with Electron 8 but filled with Electron 7.

//cc @deepak1556 
shell/common/api/electron_api_clipboard.cc
gin_helper::Arguments* args) {
  ui::ScopedClipboardWriter writer(GetClipboardBuffer(args));
  SkBitmap orig = image.AsBitmap();
  SkBitmap bmp;
  if (bmp.tryAllocPixels(orig.info()) &&
      orig.readPixels(bmp.info(), bmp.getPixels(), bmp.rowBytes(), 0, 0)) {
    writer.WriteImage(bmp);
  }
}
#if !defined(OS_MACOSX)
void Clipboard::WriteFindText(const base::string16& text) {}
base::string16 Clipboard::ReadFindText() {
  return base::string16();
}
#endif
void Clipboard::Clear(gin_helper::Arguments* args) {
  ui::Clipboard::GetForCurrentThread()->Clear(GetClipboardBuffer(args));
}
}  
}  
namespace {
void Initialize(v8::Local<v8::Object> exports,