[dotnet] there is more than one place that needs selenium manager logic added

Author: titusfortner

dotnet/src/webdriver/DriverService.cs

@@ -65,7 +65,23 @@ protected DriverService(string servicePath, int port, string driverServiceExecut
             string executablePath = Path.Combine(servicePath, driverServiceExecutableName);
             if (!File.Exists(executablePath))
             {
-                throw new DriverServiceNotFoundException(string.Format(CultureInfo.InvariantCulture, "The file {0} does not exist. The driver can be downloaded at {1}", executablePath, driverServiceDownloadUrl));
+                try
+                {
+                    executablePath = SeleniumManager.DriverPath(driverServiceExecutableName);
+                }
+                catch (Exception e)
+                {
+                  // No-op; entirely a fall-back feature
+                }
+
+                if (File.Exists(executablePath))
+                {
+                    servicePath = Path.GetDirectoryName(executablePath);
+                }
+                else
+                {
+                    throw new DriverServiceNotFoundException(string.Format(CultureInfo.InvariantCulture, "The file {0} does not exist. The driver can be downloaded at {1}", executablePath, driverServiceDownloadUrl));
+                }
             }
 
             this.driverServicePath = servicePath;
@@ -296,7 +312,21 @@ protected static string FindDriverServiceExecutable(string executableName, Uri d
 
             if (string.IsNullOrEmpty(serviceDirectory))
             {
-                throw new DriverServiceNotFoundException(string.Format(CultureInfo.InvariantCulture, "The {0} file does not exist in the current directory or in a directory on the PATH environment variable. The driver can be downloaded at {1}.", executableName, downloadUrl));
+                try
+                {
+                    serviceDirectory = Path.GetDirectoryName(SeleniumManager.DriverPath(executableName));
+                }
+                catch (Exception e)
+                {
+                    // No-op; entirely a fall-back feature
+                }
+
+                if (string.IsNullOrEmpty(serviceDirectory))
+                {
+                    throw new DriverServiceNotFoundException(string.Format(CultureInfo.InvariantCulture,
+                        "The {0} file does not exist in the current directory or in a directory on the PATH environment variable. The driver can be downloaded at {1}.",
+                        executableName, downloadUrl));
+                }
             }
 
             return serviceDirectory;