* Output of `node_modules/.bin/electron --version`: 3.0.9 (and up)
* Operating System (Platform and Version): Windows 10
* Output of `node_modules/.bin/electron --version` on last known working Electron version (if applicable): 2.0.x

**Expected Behavior**
Pressing `Ctrl + Shift + V` should result in one paste event only.

**Actual behavior**
Pressing `Ctrl + Shift + V` results in two paste events only.

**To Reproduce**
@brenca was nice enough to make a Fiddle (https://gist.github.com/brenca/e0ca153755979bed51a991e9d8c185bb). 

**Additional Notes**
A few notes that are interesting:
 * This bug is Windows-only.
 * Not registering a `paste` handler: No issue
 * Not calling `event.preventDefault()` or `event.returnValue = false`: No issue
 * Just clicking on a `MenuItem` that calls `webContents.pasteAndMatchStyle()`: No issue
 * Not registering a `MenuItem` with an accelerator: No issue
 * Chromium 66 does not have this issue


atom/browser/ui/accelerator_util.cc
switch (code) {
      
      case ui::VKEY_SHIFT:
        modifiers |= ui::EF_SHIFT_DOWN;
        break;
      case ui::VKEY_CONTROL:
        modifiers |= ui::EF_CONTROL_DOWN;
        break;
      case ui::VKEY_MENU:
        modifiers |= ui::EF_ALT_DOWN;
        break;
      case ui::VKEY_COMMAND:
        modifiers |= ui::EF_COMMAND_DOWN;
        break;
      case ui::VKEY_ALTGR:
        modifiers |= ui::EF_ALTGR_DOWN;
        break;
      
      default:
        key = code;
    }
  }
  if (key == ui::VKEY_UNKNOWN) {
    LOG(WARNING) << shortcut << " doesn't contain a valid key";
    return false;
  }
  *accelerator = ui::Accelerator(key, modifiers);
  return true;
}
void GenerateAcceleratorTable(AcceleratorTable* table,