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### Issue Details
`webContents.openDevTools();` produces error:
`[12703:1102/100312.745262:ERROR:CONSOLE(1)] "Uncaught TypeError: Cannot read property 'setDockSide' of undefined", source: devtools://devtools/bundled/devtools_app.html?remoteBase=https://chrome-devtools-frontend.appspot.com/serve_file/@1eb8474cd7e4fccfbfa8048eceda1eab8b4d394/&can_dock=true&toolbarColor=rgba(223,223,223,1)&textColor=rgba(0,0,0,1)&experiments=true (1)`

Opening dev tools via these methods also produces the same error:
* Right click background > Inspect element
* Ctrl-Shift-I

* **Electron Version:**
  * 11.0.0-beta.18
* **Operating System:**
  * Debian 10 Buster x64, KDE Plasma
* **Last Known Working Electron version:**
  * 10.1.4

### Expected Behavior
Dev tools should open without error.

### Actual Behavior
Above error appears in the terminal.

### To Reproduce
Running this code will probably do it, although I'm opening a URL, but that shouldn't matter.
https://www.electronjs.org/docs/tutorial/quick-start#create-a-basic-application

### Additional Information
I need the beta because the stable version's node is too old.
shell/browser/ui/inspectable_web_contents.cc
#include "content/public/browser/navigation_handle.h"
#include "content/public/browser/render_frame_host.h"
#include "content/public/browser/render_view_host.h"
#include "content/public/browser/shared_cors_origin_access_list.h"
#include "content/public/browser/storage_partition.h"
#include "content/public/common/user_agent.h"
#include "ipc/ipc_channel.h"
#include "net/http/http_response_headers.h"
#include "services/network/public/cpp/simple_url_loader.h"
#include "services/network/public/cpp/simple_url_loader_stream_consumer.h"
#include "services/network/public/cpp/wrapper_shared_url_loader_factory.h"
#include "shell/browser/ui/inspectable_web_contents_delegate.h"
#include "shell/browser/ui/inspectable_web_contents_view.h"
#include "shell/browser/ui/inspectable_web_contents_view_delegate.h"
#include "shell/common/platform_util.h"
#include "third_party/blink/public/common/logging/logging_utils.h"
#include "third_party/blink/public/common/page/page_zoom.h"
#include "ui/display/display.h"
#include "ui/display/screen.h"
#if BUILDFLAG(ENABLE_ELECTRON_EXTENSIONS)
#include "chrome/common/extensions/chrome_manifest_url_handlers.h"
#include "content/public/browser/child_process_security_policy.h"
#include "content/public/browser/render_process_host.h"
#include "extensions/browser/extension_registry.h"
#include "extensions/common/permissions/permissions_data.h"
#include "shell/browser/electron_browser_context.h"
#endif
namespace electron {
namespace {
const double kPresetZoomFactors[] = {0.25, 0.333, 0.5,  0.666, 0.75, 0.9,