Add a User-Agent header for Ruby HTTP requests.

Signed-off-by: Alex Rodionov <p0deje@gmail.com>

Author: Steven Hazel

rb/lib/selenium-webdriver.rb

@@ -16,3 +16,7 @@
 # under the License.
 
 require 'selenium/webdriver'
+
+module Selenium
+  VERSION = "3.11.0".freeze
+end

rb/lib/selenium/webdriver/remote/http/common.rb

@@ -24,7 +24,8 @@ class Common
           CONTENT_TYPE    = 'application/json'.freeze
           DEFAULT_HEADERS = {
             'Accept' => CONTENT_TYPE,
-            'Content-Type' => "#{CONTENT_TYPE}; charset=UTF-8"
+            'Content-Type' => "#{CONTENT_TYPE}; charset=UTF-8",
+            'User-Agent' => "selenium/#{Selenium::VERSION} (ruby #{Platform.os})"
           }.freeze
 
           attr_accessor :timeout

rb/selenium-webdriver.gemspec

@@ -1,9 +1,10 @@
 root = File.expand_path(File.dirname(__FILE__))
 raise "cwd must be #{root} when reading gemspec" if root != Dir.pwd
+require 'selenium'
 
 Gem::Specification.new do |s|
   s.name = 'selenium-webdriver'
-  s.version = '3.11.0'
+  s.version = Selenium::VERSION
 
   s.authors = ['Alex Rodionov', 'Titus Fortner']
   s.email = ['p0deje@gmail.com', 'titusfortner@gmail.com']

rb/spec/unit/selenium/webdriver/remote/http/common_spec.rb

@@ -32,6 +32,20 @@ module Http
 
             common.call(:post, 'clear', nil)
           end
+
+          it 'sends a standard User-Agent by default' do
+            common = Common.new
+            common.server_url = URI.parse('http://server')
+
+            expect(common).to receive(:request)
+              .with(:post, URI.parse('http://server/session'),
+                    hash_including(
+                      'User-Agent' =>
+                      a_string_matching(/^selenium\/#{Selenium::VERSION} \(ruby .*\)$/)),
+                    '{}')
+
+            common.call(:post, 'session', nil)
+          end
         end
       end # Http
     end # Remote