For #401, add a new rake task to update the copyright notices in all source code

    ./go copyright:update

This task ensures the copyright notice dictated in CONTRIBUTING.md is applied
at the top of every file and standardizes on a line-comment format.

The task currently covers the java/, py/, and javascript/ trees.

Close #405.

Author: jleyba

Rakefile

@@ -39,6 +39,7 @@ require 'rake-tasks/selenium'
 require 'rake-tasks/se-ide'
 require 'rake-tasks/ie_code_generator'
 require 'rake-tasks/ci'
+require 'rake-tasks/copyright'
 
 require 'rake-tasks/gecko_sdks'
 
@@ -715,6 +716,36 @@ task :authors do
   sh "(git log --use-mailmap --format='%aN <%aE>' ; cat .OLD_AUTHORS) | sort -uf > AUTHORS"
 end
 
+namespace :copyright do
+  task :update do
+    Copyright.Update(
+        FileList["javascript/**/*.js"].exclude(
+            "javascript/atoms/test/jquery.min.js",
+            "javascript/firefox-driver/extension/components/httpd.js",
+            "javascript/jsunit/**/*.js",
+            "javascript/node/selenium-webdriver/node_modules/**/*.js",
+            "javascript/selenium-core/lib/**/*.js",
+            "javascript/selenium-core/scripts/ui-element.js",
+            "javascript/selenium-core/scripts/ui-map-sample.js",
+            "javascript/selenium-core/scripts/user-extensions.js",
+            "javascript/selenium-core/scripts/xmlextras.js",
+            "javascript/selenium-core/xpath/**/*.js"))
+    Copyright.Update(
+        FileList["py/**/*.py"],
+        :style => "#",
+        :prefix => "#!/usr/bin/python\n#\n")
+    Copyright.Update(
+        FileList["java/**/*.java"].exclude(
+            "java/client/src/org/openqa/selenium/internal/Base64Encoder.java",
+            "java/client/test/org/openqa/selenium/internal/Base64EncoderTest.java",
+            "java/server/src/cybervillains/**/*.java",
+            "java/server/src/org/openqa/selenium/server/FrameGroupCommandQueueSet.java",
+            "java/server/src/org/openqa/selenium/server/FutureFileResource.java",
+            "java/server/src/org/openqa/selenium/server/ProxyHandler.java"
+            ))
+  end
+end
+
 at_exit do
   if File.exist?(".git") && !Platform.windows?
     sh "sh .git-fixfiles"

rake-tasks/copyright.rb

@@ -0,0 +1,61 @@
+module Copyright
+    NOTICE = <<-eos
+Licensed to the Software Freedom Conservancy (SFC) under one
+or more contributor license agreements.  See the NOTICE file
+distributed with this work for additional information
+regarding copyright ownership.  The SFC licenses this file
+to you under the Apache License, Version 2.0 (the
+"License"); you may not use this file except in compliance
+with the License.  You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing,
+software distributed under the License is distributed on an
+"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, either express or implied.  See the License for the
+specific language governing permissions and limitations
+under the License.
+eos
+
+  def Update(files, options = {})
+    style = options[:style] || "//"
+    prefix = options[:prefix] || nil
+
+    notice = Copyright::NOTICE.split(/\n/).map{|line|
+      (style + " " + line).rstrip + "\n"
+    }.join("")
+    notice = prefix + notice unless prefix.nil?
+
+    files.each do |f|
+      lines = IO.readlines(f)
+
+      index = -1
+      lines.any? {|line|
+        done = true
+        if line.index(style) == 0
+          index += 1
+          done = false
+        end
+        done
+      }
+      if index == -1
+        puts "Adding notice to #{f}"
+        File.open(f, "w") do |f|
+          f.write(notice + "\n")
+          lines.each {|line| f.write(line) }
+        end
+      else
+        current = lines.shift(index + 1).join("")
+        if current != notice
+          puts "Updating notice in #{f}"
+          File.open(f, "w") do |f|
+            f.write(notice)
+            lines.each {|line| f.write(line) }
+          end
+        end
+      end
+    end
+  end
+  module_function :Update
+end