4 files changed, 0 insertions, 67 deletions
diff --git a/actionpack/lib/action_dispatch.rb b/actionpack/lib/action_dispatch.rb
index 9ab048b756..618e2f3033 100644
--- a/actionpack/lib/action_dispatch.rb
+++ b/actionpack/lib/action_dispatch.rb
@@ -47,7 +47,6 @@ module ActionDispatch
 
   autoload_under 'middleware' do
     autoload :RequestId
-    autoload :BestStandardsSupport
     autoload :Callbacks
     autoload :Cookies
     autoload :DebugExceptions
diff --git a/actionpack/lib/action_dispatch/middleware/best_standards_support.rb b/actionpack/lib/action_dispatch/middleware/best_standards_support.rb
deleted file mode 100644
index 94efeb79fa..0000000000
--- a/actionpack/lib/action_dispatch/middleware/best_standards_support.rb
+++ /dev/null
@@ -1,30 +0,0 @@
-module ActionDispatch
-  class BestStandardsSupport
-    def initialize(app, type = true)
-      @app = app
-
-      @header = case type
-      when true
-        "IE=Edge,chrome=1"
-      when :builtin
-        "IE=Edge"
-      when false
-        nil
-      end
-    end
-
-    def call(env)
-      status, headers, body = @app.call(env)
-
-      if headers["X-UA-Compatible"] && @header
-        unless headers["X-UA-Compatible"][@header]
-          headers["X-UA-Compatible"] << "," << @header.to_s
-        end
-      else
-        headers["X-UA-Compatible"] = @header
-      end
-
-      [status, headers, body]
-    end
-  end
-end
diff --git a/actionpack/lib/action_dispatch/railtie.rb b/actionpack/lib/action_dispatch/railtie.rb
index 5a835ae439..2dfaab3587 100644
--- a/actionpack/lib/action_dispatch/railtie.rb
+++ b/actionpack/lib/action_dispatch/railtie.rb
@@ -6,7 +6,6 @@ module ActionDispatch
     config.action_dispatch.x_sendfile_header = nil
     config.action_dispatch.ip_spoofing_check = true
     config.action_dispatch.show_exceptions = true
-    config.action_dispatch.best_standards_support = true
     config.action_dispatch.tld_length = 1
     config.action_dispatch.ignore_accept_header = false
     config.action_dispatch.rescue_templates = { }
diff --git a/actionpack/test/dispatch/best_standards_support_test.rb b/actionpack/test/dispatch/best_standards_support_test.rb
deleted file mode 100644
index 551bb9621a..0000000000
--- a/actionpack/test/dispatch/best_standards_support_test.rb
+++ /dev/null
@@ -1,35 +0,0 @@
-require 'abstract_unit'
-
-class BestStandardsSupportTest < ActiveSupport::TestCase
-  def test_with_best_standards_support
-    _, headers, _ = app(true, {}).call({})
-    assert_equal "IE=Edge,chrome=1", headers["X-UA-Compatible"]
-  end
-
-  def test_with_builtin_best_standards_support
-    _, headers, _ = app(:builtin, {}).call({})
-    assert_equal "IE=Edge", headers["X-UA-Compatible"]
-  end
-
-  def test_without_best_standards_support
-    _, headers, _ = app(false, {}).call({})
-    assert_equal nil, headers["X-UA-Compatible"]
-  end
-
-  def test_appends_to_app_headers_without_duplication_after_multiple_requests
-    app_headers = { "X-UA-Compatible" => "requiresActiveX=true" }
-    _, headers, _ = app(true, app_headers).call({})
-    _, headers, _ = app(true, app_headers).call({})
-
-    expects = "requiresActiveX=true,IE=Edge,chrome=1"
-    assert_equal expects, headers["X-UA-Compatible"]
-  end
-
-  private
-
-    def app(type, headers)
-      app = proc { [200, headers, "response"] }
-      ActionDispatch::BestStandardsSupport.new(app, type)
-    end
-
-end