request: add support for creating browsers in different contexts

[jepp]

I've been working with testing some of the new SetPreferences features (as noted in my other thread about dynamically changing the proxy). As part of testing some network issues, I wanted to put several TChromium instances in one app, each with a different proxy. But I eventually noticed that when I used SetPreferences, the change was global. This is because crm.Browser.Host.RequestContext is shared among the different instances. I dug down and here's how I changed it so that each browser got their own context:

procedure TCustomChromium.CreateBrowser;
var
  info: TCefWindowInfo;
  rect: TRect;
  settings: TCefBrowserSettings;
  contextSettings: TCefRequestContextSettings;
  context: ICefRequestContext;
begin
  if not (csDesigning in ComponentState) then
  begin
    FillChar(info, SizeOf(info), 0);
    rect := GetClientRect;
    info.Style := WS_CHILD or WS_VISIBLE or WS_CLIPCHILDREN or WS_CLIPSIBLINGS or WS_TABSTOP;
    info.parent_window := Handle;
    info.x := rect.left;
    info.y := rect.top;
    info.Width := rect.right - rect.left;
    info.Height := rect.bottom - rect.top;
    FillChar(settings, SizeOf(TCefBrowserSettings), 0);
    settings.size := SizeOf(TCefBrowserSettings);
    GetSettings(settings);
    //contextHandler := TCefRequestContextHandlerRef.
    FillChar(contextSettings, SizeOf(contextSettings), 0);
    contextSettings.size := SizeOf(contextSettings);
    context := TCefRequestContextRef.New(@contextSettings, nil);
{$IFDEF CEF_MULTI_THREADED_MESSAGE_LOOP}
//    CefBrowserHostCreate(@info, FHandler, FDefaultUrl, @settings, nil);
    CefBrowserHostCreate(@info, FHandler, FDefaultUrl, @settings, context);
{$ELSE}
//    FBrowser := CefBrowserHostCreateSync(@info, FHandler, '', @settings, nil);
    FBrowser := CefBrowserHostCreateSync(@info, FHandler, '', @settings, context);
    FBrowserId := FBrowser.Identifier;
{$ENDIF}
  end;
end;

First, does this look correct or have I messed anything up? Do you know of anything wrong with passing in nil to the TCefRequestContextRef.New call?

This is working for me, at least with CEF_MULTI_THREADED_MESSAGE_LOOP turned off.

I was thinking was that TChromium could have a property like UseNewContext and if it was set, then CreateBrowser could use a different context for that one. Otherwise, it would use the global context.

What do you think?