Default connection class to ActionCable::Connection::Base.

Instead of depending on ApplicationCable::Connection being defined at initialize
we should inject it in the Railtie.

Thus we can kill more setup in the tests too.

actioncable/lib/action_cable/engine.rb

@@ -31,6 +31,10 @@ class Railtie < Rails::Engine # :nodoc:
           self.cable = Rails.application.config_for(config_path).with_indifferent_access
         end
 
+        if 'ApplicationCable::Connection'.safe_constantize
+          self.connection_class = ApplicationCable::Connection
+        end
+
         self.channel_paths = Rails.application.paths['app/channels'].existent
 
         options.each { |k,v| send("#{k}=", v) }

actioncable/lib/action_cable/server/configuration.rb

@@ -13,8 +13,8 @@ class Configuration
       def initialize
         @log_tags = []
 
-        @connection_class  = ApplicationCable::Connection
-        @worker_pool_size  = 100
+        @connection_class = ActionCable::Connection::Base
+        @worker_pool_size = 100
 
         @disable_request_forgery_protection = false
       end

actioncable/test/client_test.rb

@@ -13,9 +13,6 @@ class ClientTest < ActionCable::TestCase
 
   def setup
     # TODO: ActionCable requires a *lot* of setup at the moment...
-    ::Object.const_set(:ApplicationCable, Module.new)
-    ::ApplicationCable.const_set(:Connection, Class.new(ActionCable::Connection::Base))
-
     ActionCable.instance_variable_set(:@server, nil)
     server = ActionCable.server
     inner_logger = Logger.new(StringIO.new).tap { |l| l.level = Logger::UNKNOWN }
@@ -36,11 +33,6 @@ def setup
 
   def teardown
     $VERBOSE = @previous_verbose
-
-    begin
-      ::Object.send(:remove_const, :ApplicationCable)
-    rescue NameError
-    end
   end
 
   def with_puma_server(rack_app = ActionCable.server, port = 3099)

actioncable/test/subscription_adapter/common.rb

@@ -10,9 +10,6 @@ module CommonSubscriptionAdapterTest
 
   def setup
     # TODO: ActionCable requires a *lot* of setup at the moment...
-    ::Object.const_set(:ApplicationCable, Module.new)
-    ::ApplicationCable.const_set(:Connection, Class.new(ActionCable::Connection::Base))
-
     server = ActionCable::Server::Base.new
     inner_logger = Logger.new(StringIO.new).tap { |l| l.level = Logger::UNKNOWN }
     server.config.logger = ActionCable::Connection::TaggedLoggerProxy.new(inner_logger, tags: [])
@@ -30,11 +27,6 @@ def setup
   def teardown
     @tx_adapter.shutdown if @tx_adapter && @tx_adapter != @rx_adapter
     @rx_adapter.shutdown if @rx_adapter
-
-    begin
-      ::Object.send(:remove_const, :ApplicationCable)
-    rescue NameError
-    end
   end