- Electron version: 1.4.0
- Operating system: OS X 10.10.5

I've been using the following code to send Tab key events to a webview in my project:

``` js
const webContents = webView.getWebContents();
const keyEvent = {
  type: 'keyDown',
  keyCode: 'Tab'
};

webContents.sendInputEvent(keyEvent);
```

I have had no issues with this until the recent update to 1.4.0.

The last version the above code works in OS X is **1.3.7**. I've tried this with the latest versions of Electron (1.4.1 & 1.4.2) with the same results.

Am I doing something wrong here? Is this a known issue?

atom/common/keyboard_util.cc
c = base::ToLowerASCII(c);
  *shifted = false;
  switch (c) {
    case 0x08: return ui::VKEY_BACK;
    case 0x7F: return ui::VKEY_DELETE;
    case 0x09: return ui::VKEY_TAB;
    case 0x0D: return ui::VKEY_RETURN;
    case 0x1B: return ui::VKEY_ESCAPE;
    case ' ': return ui::VKEY_SPACE;
    case 'a': return ui::VKEY_A;
    case 'b': return ui::VKEY_B;
    case 'c': return ui::VKEY_C;
    case 'd': return ui::VKEY_D;
    case 'e': return ui::VKEY_E;
    case 'f': return ui::VKEY_F;
    case 'g': return ui::VKEY_G;
    case 'h': return ui::VKEY_H;
    case 'i': return ui::VKEY_I;
    case 'j': return ui::VKEY_J;
    case 'k': return ui::VKEY_K;
    case 'l': return ui::VKEY_L;
    case 'm': return ui::VKEY_M;
    case 'n': return ui::VKEY_N;
    case 'o': return ui::VKEY_O;
    case 'p': return ui::VKEY_P;
    case 'q': return ui::VKEY_Q;
    case 'r': return ui::VKEY_R;
    case 's': return ui::VKEY_S;
    case 't': return ui::VKEY_T;
    case 'u': return ui::VKEY_U;