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### Issue Details
Electron Version: All Version
Operating System: macOS 10.15.3
Last Known Working Electron version: Never

### Bug
The color picker in devtools does not work.
In devtools if you want to change the colors of the CSS code. When you click on a color a color picker is supposed to appear but it does not appear.

### Screenshots
<img width="1013" alt="Capture d’écran 2020-09-07 à 11 42 44" src="https://user-images.githubusercontent.com/70572698/92374841-988ea280-f100-11ea-96be-afc93f6dd645.png">

shell/browser/api/electron_api_web_contents.cc
if (IsOffScreen()) {
#if BUILDFLAG(ENABLE_OSR)
    auto* osr_rwhv = GetOffScreenRenderWidgetHostView();
    if (osr_rwhv)
      osr_rwhv->Invalidate();
#endif
  } else {
    auto* const window = owner_window();
    if (window)
      window->Invalidate();
  }
}
gfx::Size WebContents::GetSizeForNewRenderView(content::WebContents* wc) {
  if (IsOffScreen() && wc == ontents()) {
    auto* relay = NativeWindowRelay::FromWebContents(ontents());
    if (relay) {
      auto* owner_window = relay->GetNativeWindow();
      return owner_window ? owner_window->GetSize() : gfx::Size();
    }
  }
  return gfx::Size();
}
void WebContents::SetZoomLevel(double level) {
  zoom_controller_->SetZoomLevel(level);
}
double WebContents::GetZoomLevel() const {
  return zoom_controller_->GetZoomLevel();
}
void WebContents::SetZoomFactor(gin_helper::ErrorThrower thrower,