[Windows] Refactor virtual-env image generation provisioners (#1288)

* refactor virtual-env image generation provisioners

images/win/scripts/ImageHelpers/InstallHelpers.ps1

@@ -63,68 +63,6 @@ function Install-Binary
     }
 }
 
-Function Install-VisualStudio
-{
-    <#
-    .SYNOPSIS
-        A helper function to install Visual Studio.
-
-    .DESCRIPTION
-        Prepare system environment, and install Visual Studio bootstrapper with selected workloads.
-
-    .PARAMETER BootstrapperUrl
-        The URL from which the bootstrapper will be downloaded. Required parameter.
-
-    .PARAMETER WorkLoads
-        The string that contain workloads that will be passed to the installer.
-    #>
-
-    Param
-    (
-        [Parameter(Mandatory)]
-        [String] $BootstrapperUrl,
-        [String] $WorkLoads
-    )
-
-    Write-Host "Downloading Bootstrapper ..."
-    $BootstrapperName = [IO.Path]::GetFileName($BootstrapperUrl)
-    $bootstrapperFilePath = Start-DownloadWithRetry -Url $BootstrapperUrl -Name $BootstrapperName
-
-    try
-    {
-        Write-Host "Enable short name support on Windows needed for Xamarin Android AOT, defaults appear to have been changed in Azure VMs"
-        $shortNameEnableProcess = Start-Process -FilePath fsutil.exe -ArgumentList ('8dot3name', 'set', '0') -Wait -PassThru
-
-        $shortNameEnableExitCode = $shortNameEnableProcess.ExitCode
-        if ($shortNameEnableExitCode -ne 0)
-        {
-            Write-Host "Enabling short name support on Windows failed. This needs to be enabled prior to VS 2017 install for Xamarin Andriod AOT to work."
-            exit $shortNameEnableExitCode
-        }
-
-        Write-Host "Starting Install ..."
-        $bootstrapperArgumentList = ('/c', $bootstrapperFilePath, $WorkLoads, '--quiet', '--norestart', '--wait', '--nocache' )
-        $process = Start-Process -FilePath cmd.exe -ArgumentList $bootstrapperArgumentList -Wait -PassThru
-
-        $exitCode = $process.ExitCode
-        if ($exitCode -eq 0 -or $exitCode -eq 3010)
-        {
-            Write-Host "Installation successful"
-            return $exitCode
-        }
-        else
-        {
-            Write-Host "Non zero exit code returned by the installation process : $exitCode"
-            exit $exitCode
-        }
-    }
-    catch
-    {
-        Write-Host "Failed to install Visual Studio; $($_.Exception.Message)"
-        exit -1
-    }
-}
-
 function Stop-SvcWithErrHandling
 {
     <#
@@ -464,36 +402,6 @@ function Extract-7Zip {
     }
 }
 
-function Get-VsCatalogJsonPath {
-    $instanceFolder = Get-Item "C:\ProgramData\Microsoft\VisualStudio\Packages\_Instances\*" | Select-Object -First 1
-    return Join-Path $instanceFolder.FullName "catalog.json"
-}
-
-function Get-VisualStudioPath {
-    Param
-    (
-        [Parameter(Mandatory=$true)]
-        [string]$Version,
-        [Parameter(Mandatory=$true)]
-        [string]$Edition
-    )
-
-    return "${env:ProgramFiles(x86)}\Microsoft Visual Studio\${Version}\${Edition}"
-}
-
-function Get-VisualStudioPackages
-{
-    $packagePath = "$env:ProgramData\Microsoft\VisualStudio\Packages\_Instances\*\state.packages.json"
-    $instanceFolders = Get-ChildItem -Path $packagePath
-    (Get-Content -Path $instanceFolders | ConvertFrom-Json).packages
-}
-
-function Get-VisualStudioComponents {
-    $vsPackages = Get-VisualStudioPackages | Where-Object type -in 'Component', 'Workload'
-    $vsPackages  | Sort-Object Id | Select-Object @{n = 'Package'; e = {$_.Id}} |
-    Where-Object { $_.Package -notmatch "[0-9a-fA-F]{8}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{12}" }
-}
-
 function Install-AndroidSDKPackages {
     Param
     (