Remove CefBrowserSettings.accept_language_list

[rstedman]

Describe the bug
This bug is described in this forum thread - https://magpcss.org/ceforum/viewtopic.php?f=6&t=18880. The thread has a post from a user that debugged the issue and describes why the problem is occurring.

I am experiencing the exact behavior described here using CefSharp 115.3.130. I tried using the workaround described in the thread of creating a browser instance with a new CefRequestContext and specifying the accept language list in the CefRequestContextSettings, and while this did address the Accept-Langauge issue it also caused a number of other more significant issues and had to be reverted.

To Reproduce
Steps to reproduce the behavior:

• In SimpleApp::OnContextInitialized, add this line before before CreateBrowser call:

CefString(&browser_settings.accept_language_list) = "de";

• Build & run, confirm Google homepage is shown in German
• In SimpleHandler.h, add CefRequestHandler and CefResourceRequestHandler to list of base classes and override GetRequestHandler & GetResourceRequestHandler:

  virtual CefRefPtr<CefRequestHandler> GetRequestHandler() override  {
      return this;
  }
  virtual CefRefPtr<CefResourceRequestHandler> GetResourceRequestHandler(
      CefRefPtr<CefBrowser> browser,
      CefRefPtr<CefFrame> frame,
      CefRefPtr<CefRequest> request,
      bool is_navigation,
      bool is_download,
      const CefString& request_initiator,
      bool& disable_default_handling) override {
      return this;
  }

• Build & run again, Google homepage is now in English. Checking request headers with dev tools Network tab shows Accept-Language is using default value of en-US.

Expected behavior
The CefBrowserSettings.accept_language_list is respected when using a ResourceRequestHandler

Versions (please complete the following information):

• OS: Windows 10
• CEF Version: 115.3.13

Additional context
Does the problem reproduce with the cefclient or cefsimple sample application at the same version?

Yes - the initial post on the forum thread describes how to reproduce the issue with cefsimple

Does the problem reproduce with Google Chrome at the same version?

No

Add any other context about the problem here.

[magreenblatt]

From the forum thread:

I've debugged the network process and found URLRequestHttpJob is intialised with a StaticHttpUserAgentSettings object, which itself is initialised from a network::mojom::NetworkContextParams. I found a NetworkContextParams object initialised in ChromeContentBrowserClientCef::ConfigureNetworkContextParams, presumably in one of the other processes but I couldn't hit a breakpoint on this one even attaching to all processes, maybe it gets called before I attach. Anyway, this method also calls browser_prefs::GetAcceptLanguageList but passes in a null for the browser parameter, so it only gets the language list from the context settings or global settings, but not the browser settings.

This means if I create a CefRequestContext instance and specify the language list on CefRequestContextSettings, and pass that context to CreateBrowser the correct languages are used, even with GetResourceRequestHandler on my CefClient class. This is an acceptable workaround, but I think it should still work setting accept_language_list on CefBrowserSettings as well.

Based on that description you can set accept_language_list on either the CefSettings or the CefRequestContextSettings to work around the issue currently.

[magreenblatt]

We should remove CefBrowserSettings.accept_language_list as the option needs to be configured globally, or at the request context level via the language::prefs::kSelectedLanguages preference. See related issue #3579.