Remove global BROWSER and use browser helper

app/controllers/application_controller.rb

@@ -2,7 +2,6 @@ class ApplicationController < ActionController::Base
   # Prevent CSRF attacks by raising an exception.
   # For APIs, you may want to use :null_session instead.
   protect_from_forgery with: :exception
-  before_action :check_browser
   before_action :load_navbar_left_pannel_partial_url
   before_action :set_raven_context
   before_action :authorize_request_for_profiler
@@ -26,10 +25,6 @@ class ApplicationController < ActionController::Base
     {}
   end
 
-  def check_browser
-    BROWSER.value = BrowserService.get_browser(request)
-  end
-
   def load_navbar_left_pannel_partial_url
     controller = request.controller_class
     method = params[:action]