Use this code to delete Cookies from Chromium Version CEF3:
Use c_WB_ClearCookies for deleating all Cookies
Use c_WB_Clear_url_Cookies for deleating all Cookies only from one speceally 
Url like this -> c_WB_Clear_url_Cookies('http://google.com','cookie_name');
type
  CefTask = class(TCefTaskOwn)
    procedure Execute; override;
    public
    var url,cookieName: ustring;
    constructor create; virtual;
  end;
constructor CefTask.create;
begin
  inherited create;
  url := '';
  cookieName := '';
end;
procedure CefTask.Execute;
var CookieManager: ICefCookieManager;
begin
  CookieManager := TCefCookieManagerRef.Global;
  CookieManager.DeleteCookies(url,cookieName);
end;
procedure c_WB_ClearCookies;
var Task: CefTask;
begin
  Task := CefTask.Create;
  CefPostTask(TID_IO, Task);
end;
// c_WB_Clear_url_Cookies('http://google.com','cookie_name');
procedure c_WB_Clear_url_Cookies(c_url,c_cookieName: ustring);
var Task: CefTask;
begin
  Task := CefTask.Create;
  Task.url := c_url;
  Task.cookieName := c_cookieName;
  CefPostTask(TID_IO, Task);
end;
For list all Cookies to get the cookieName use Procedure list_all_cookies
procedure pausek;
var M: TMsg;
begin
  while PeekMessage(M, 0, 0, 0, pm_Remove) do
    begin
      TranslateMessage(M);
      DispatchMessage(M);
    end;
end;
procedure pause(i:longint);
var j : nativeint;
begin
  for j := 1 to i do
    begin
      pausek;
      sleep(100);
    end;
end;
procedure list_all_cookies;
var CookieManager: ICefCookieManager;
    cookie_list : string;
const lf = chr(13) + chr(10); 
begin
  cookie_list := '';
  CookieManager := TCefCookieManagerRef.Global;
  CookieManager.VisitAllCookiesProc(
    function(const name, value, domain, path: ustring; secure, httponly,
      hasExpires: Boolean; const creation, lastAccess, expires: TDateTime;
      count, total: Integer; out deleteCookie: Boolean): Boolean
    begin
      cookie_list := cookie_list + inttostr(count) + ': ' +  domain + ' - ' + name + ' - ' + value + ' - ' + path + lf;
     if (count<total) then result := true;
    end
  );
  pause(10);
  ShowMessage(cookie_list);
end;