basing build-kite image on agent-windows

containers/agent-windows-buildkite/Dockerfile

@@ -1,48 +1,14 @@
 # escape=`
 
 # use windows server core image
-ARG version=ltsc2019
-FROM mcr.microsoft.com/windows/servercore:$version
-
-# install chocolately as package manager
-RUN powershell -Command `
-    iex ((new-object net.webclient).DownloadString('https://chocolatey.org/install.ps1')) ; `
-    choco feature disable --name showDownloadProgress
-
-# install Visual Studio build tools
-RUN powershell -NoProfile -InputFormat None -Command `
-    choco install visualcpp-build-tools `
-        --version 15.0.26228.20170424 -y --params "'/IncludeOptional'" ;`
-    Write-Host 'Waiting for Visual C++ Build Tools to finish'; `
-    Wait-Process -Name vs_installer
-
-# install other tools as described in https://llvm.org/docs/GettingStartedVS.html
-# and a few more that were not documented...
-RUN choco install -y git & `
-    choco install -y cmake --version 3.15.4 & `
-    choco install -y python2 & `
-    choco install -y gnuwin32-coreutils.install & `
-    choco install -y ninja & `
-    choco install -y grep & ` 
-    choco install -y sed & ` 
-    choco install -y diffutils
-RUN pip install psutil    
-
-# configure Python encoding
-ENV PYTHONIOENCODING=UTF-8
-
-# update the path variable    
-RUN powershell.exe -Command $path = $env:path + ';c:\Program Files (x86)\GnuWin32\bin;C:\Program Files\CMake\bin'; Set-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\Environment\' -Name Path -Value $path
-
-# use this drive to store the worksapce'
-VOLUME W:
+FROM gcr.io/llvm-premerge-checks/agent-windows
 
 # install buildkite agent as described in the documentation
 # https://buildkite.com/docs/agent/v3/windows
 # Supply your agent token via the arguement "-token <mytoken" when building the image
 ARG token
 ENV buildkiteAgentToken="${token}"
-ENV BUILDKITE_BUILD_PATH=W:\buildkite
+ENV BUILDKITE_BUILD_PATH=C:\workspace\buildkite
 ENV BUILDKITE_AGENT_NAME=amd64-windows-visualstudio2017
 
 RUN powershell -NoProfile -InputFormat None -Command `