Adding the DriverProcessStarting event to the .NET DriverService object

This event gives users the ability to modify the ProcessStartInfo instance
used to start the executable for the given DriverService. Possible use
cases include being able to redirect the streams for stdin, stdout and
stderr, or running the driver service executable as a different user
context than the user currently logged into the machine.

dotnet/src/webdriver/DriverProcessStartingEventArgs.cs

@@ -0,0 +1,50 @@
+// <copyright file="DriverProcessStartingEventArgs.cs" company="WebDriver Committers">
+// 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.
+// </copyright>
+
+using System;
+using System.Diagnostics;
+
+namespace OpenQA.Selenium
+{
+    /// <summary>
+    /// Provides data for the DriverProcessStarting event of a <see cref="DriverService"/> object.
+    /// </summary>
+    public class DriverProcessStartingEventArgs : EventArgs
+    {
+        private ProcessStartInfo startInfo;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="DriverProcessStartingEventArgs"/> class.
+        /// </summary>
+        /// <param name="startInfo">The <see cref="ProcessStartInfo"/> of the
+        /// driver process to be started.</param>
+        public DriverProcessStartingEventArgs(ProcessStartInfo startInfo)
+        {
+            this.startInfo = startInfo;
+        }
+
+        /// <summary>
+        /// Gets the <see cref="ProcessStartInfo"/> object with which the
+        /// driver service process will be started.
+        /// </summary>
+        public ProcessStartInfo DriverServiceProcessStartInfo
+        {
+            get { return this.startInfo; }
+        }
+    }
+}

dotnet/src/webdriver/DriverService.cs

@@ -72,6 +72,8 @@ protected DriverService(string servicePath, int port, string driverServiceExecut
             this.driverServicePort = port;
         }
 
+        public event EventHandler<DriverProcessStartingEventArgs> DriverProcessStarting;
+
         /// <summary>
         /// Gets the Uri of the service.
         /// </summary>
@@ -250,6 +252,10 @@ public void Start()
             this.driverServiceProcess.StartInfo.Arguments = this.CommandLineArguments;
             this.driverServiceProcess.StartInfo.UseShellExecute = false;
             this.driverServiceProcess.StartInfo.CreateNoWindow = this.hideCommandPromptWindow;
+
+            DriverProcessStartingEventArgs eventArgs = new DriverProcessStartingEventArgs(this.driverServiceProcess.StartInfo);
+            this.OnDriverProcessStarting(eventArgs);
+
             this.driverServiceProcess.Start();
             bool serviceAvailable = this.WaitForServiceInitialization();
 
@@ -297,6 +303,23 @@ protected virtual void Dispose(bool disposing)
             }
         }
 
+        /// <summary>
+        /// Raises the <see cref="DriverProcessStarting"/> event.
+        /// </summary>
+        /// <param name="eventArgs">A <see cref="DriverProcessStartingEventArgs"/> that contains the event data.</param>
+        protected void OnDriverProcessStarting(DriverProcessStartingEventArgs eventArgs)
+        {
+            if (eventArgs == null)
+            {
+                throw new ArgumentNullException("eventArgs", "eventArgs must not be null");
+            }
+
+            if (this.DriverProcessStarting != null)
+            {
+                this.DriverProcessStarting(this, eventArgs);
+            }
+        }
+
         /// <summary>
         /// Stops the DriverService.
         /// </summary>