* Electron version: 1.8.2
* Operating system: macos 10.13.3

Reproducing repo: https://github.com/ibash/electron-webkit-app-drag

Demonstrates a bug where `-webkit-app-region: drag` causes a browser view in front of it to miss click events. Oddly - it does not prevent hover events.

Steps:
1. Clone https://github.com/ibash/electron-webkit-app-drag, `yarn install`, `yarn start`
2. Click "button1"
3. Click "button2"

Expected:

Clicking button1 or button2 pops up an alert: "button clicked!"

Actual:

Only clicking button2 pops up an alert: "button clicked!"

atom/browser/api/atom_api_browser_window.cc
.SetMethod("setHasShadow", &BrowserWindow::SetHasShadow)
      .SetMethod("hasShadow", &BrowserWindow::HasShadow)
      .SetMethod("setOpacity", &BrowserWindow::SetOpacity)
      .SetMethod("getOpacity", &BrowserWindow::GetOpacity)
      .SetMethod("setRepresentedFilename",
                 &BrowserWindow::SetRepresentedFilename)
      .SetMethod("getRepresentedFilename",
                 &BrowserWindow::GetRepresentedFilename)
      .SetMethod("setDocumentEdited", &BrowserWindow::SetDocumentEdited)
      .SetMethod("isDocumentEdited", &BrowserWindow::IsDocumentEdited)
      .SetMethod("setIgnoreMouseEvents", &BrowserWindow::SetIgnoreMouseEvents)
      .SetMethod("setContentProtection", &BrowserWindow::SetContentProtection)
      .SetMethod("setFocusable", &BrowserWindow::SetFocusable)
      .SetMethod("focusOnWebView", &BrowserWindow::FocusOnWebView)
      .SetMethod("blurWebView", &BrowserWindow::BlurWebView)
      .SetMethod("isWebViewFocused", &BrowserWindow::IsWebViewFocused)
      .SetMethod("setProgressBar", &BrowserWindow::SetProgressBar)
      .SetMethod("setOverlayIcon", &BrowserWindow::SetOverlayIcon)
      .SetMethod("setThumbarButtons", &BrowserWindow::SetThumbarButtons)
      .SetMethod("setMenu", &BrowserWindow::SetMenu)
      .SetMethod("setAutoHideMenuBar", &BrowserWindow::SetAutoHideMenuBar)
      .SetMethod("isMenuBarAutoHide", &BrowserWindow::IsMenuBarAutoHide)
      .SetMethod("setMenuBarVisibility", &BrowserWindow::SetMenuBarVisibility)
      .SetMethod("isMenuBarVisible", &BrowserWindow::IsMenuBarVisible)
      .SetMethod("setVisibleOnAllWorkspaces",
                 &BrowserWindow::SetVisibleOnAllWorkspaces)
      .SetMethod("isVisibleOnAllWorkspaces",
                 &BrowserWindow::IsVisibleOnAllWorkspaces)
#if defined(OS_MACOSX)
      .SetMethod("setAutoHideCursor", &BrowserWindow::SetAutoHideCursor)