--- a/testing/docker/decision/Dockerfile
+++ b/testing/docker/decision/Dockerfile
@@ -3,16 +3,19 @@ MAINTAINER    Greg Arndt <garndt@mozilla
 
 # Add worker user
 RUN useradd -d /home/worker -s /bin/bash -m worker
 RUN mkdir /home/worker/artifacts && chown worker:worker /home/worker/artifacts
 
 # %include testing/docker/recipes/tooltool.py
 ADD topsrcdir/testing/docker/recipes/tooltool.py /tmp/tooltool.py
 
+# %include testing/mozharness/external_tools/robustcheckout.py
+ADD topsrcdir/testing/mozharness/external_tools/robustcheckout.py /usr/local/mercurial/robustcheckout.py
+
 # %include testing/docker/recipes/install-mercurial.sh
 ADD topsrcdir/testing/docker/recipes/install-mercurial.sh /tmp/install-mercurial.sh
 
 ADD system-setup.sh /tmp/system-setup.sh
 RUN bash /tmp/system-setup.sh
 
 # %include testing/docker/recipes/run-task
 ADD topsrcdir/testing/docker/recipes/run-task /home/worker/bin/run-task

--- a/testing/docker/desktop-test/Dockerfile
+++ b/testing/docker/desktop-test/Dockerfile
@@ -2,16 +2,19 @@ FROM          ubuntu:12.04
 MAINTAINER    Jonas Finnemann Jensen <jopsen@gmail.com>
 
 RUN useradd -d /home/worker -s /bin/bash -m worker
 WORKDIR /home/worker
 
 # %include testing/docker/recipes/tooltool.py
 ADD topsrcdir/testing/docker/recipes/tooltool.py /setup/tooltool.py
 
+# %include testing/mozharness/external_tools/robustcheckout.py
+ADD topsrcdir/testing/mozharness/external_tools/robustcheckout.py /usr/local/mercurial/robustcheckout.py
+
 # %include testing/docker/recipes/install-mercurial.sh
 ADD topsrcdir/testing/docker/recipes/install-mercurial.sh /tmp/install-mercurial.sh
 
 # Add wrapper scripts for xvfb allowing tasks to easily retry starting up xvfb
 # %include testing/docker/recipes/xvfb.sh
 ADD topsrcdir/testing/docker/recipes/xvfb.sh /home/worker/scripts/xvfb.sh
 
 # %include testing/docker/recipes/ubuntu1204-test-system-setup.sh

--- a/testing/docker/desktop1604-test/Dockerfile
+++ b/testing/docker/desktop1604-test/Dockerfile
@@ -2,16 +2,19 @@ FROM          ubuntu:16.04
 MAINTAINER    Joel Maher <joel.maher@gmail.com>
 
 RUN useradd -d /home/worker -s /bin/bash -m worker
 WORKDIR /home/worker
 
 # %include testing/docker/recipes/tooltool.py
 ADD topsrcdir/testing/docker/recipes/tooltool.py /setup/tooltool.py
 
+# %include testing/mozharness/external_tools/robustcheckout.py
+ADD topsrcdir/testing/mozharness/external_tools/robustcheckout.py /usr/local/mercurial/robustcheckout.py
+
 # %include testing/docker/recipes/install-mercurial.sh
 ADD topsrcdir/testing/docker/recipes/install-mercurial.sh /setup/install-mercurial.sh
 
 # %include testing/docker/recipes/ubuntu1604-test-system-setup.sh
 ADD topsrcdir/testing/docker/recipes/ubuntu1604-test-system-setup.sh /setup/system-setup.sh
 RUN           bash /setup/system-setup.sh
 
 # Add wrapper scripts for xvfb allowing tasks to easily retry starting up xvfb

--- a/testing/docker/lint/Dockerfile
+++ b/testing/docker/lint/Dockerfile
@@ -3,16 +3,19 @@ MAINTAINER    Andrew Halberstadt <ahalbe
 
 RUN useradd -d /home/worker -s /bin/bash -m worker
 WORKDIR /home/worker
 
 RUN mkdir /build
 # %include testing/docker/recipes/tooltool.py
 ADD topsrcdir/testing/docker/recipes/tooltool.py /build/tooltool.py
 
+# %include testing/mozharness/external_tools/robustcheckout.py
+ADD topsrcdir/testing/mozharness/external_tools/robustcheckout.py /usr/local/mercurial/robustcheckout.py
+
 # %include testing/docker/recipes/install-mercurial.sh
 ADD topsrcdir/testing/docker/recipes/install-mercurial.sh /build/install-mercurial.sh
 ADD system-setup.sh /tmp/system-setup.sh
 RUN bash /tmp/system-setup.sh
 
 # %include testing/docker/recipes/run-task
 ADD topsrcdir/testing/docker/recipes/run-task /home/worker/bin/run-task
 RUN chown -R worker:worker /home/worker/bin && chmod 755 /home/worker/bin/*

--- a/testing/docker/recipes/install-mercurial.sh
+++ b/testing/docker/recipes/install-mercurial.sh
@@ -51,28 +51,16 @@ tooltool_fetch <<EOF
 EOF
 
     dpkg -i ${HG_COMMON_FILENAME} ${HG_FILENAME}
 else
     echo "Do not know how to install Mercurial on this OS"
     exit 1
 fi
 
-mkdir -p /usr/local/mercurial
-tooltool_fetch <<'EOF'
-[
-{
-    "size": 11849,
-    "digest": "c88d9b8afd6649bd28bbacfa654ebefec8087a01d1662004aae088d485edeb03a92df1193d1310c0369d7721f475b974fcd4a911428ec65936f7e40cf1609c49",
-    "algorithm": "sha512",
-    "filename": "robustcheckout.py"
-}
-]
-EOF
-mv robustcheckout.py /usr/local/mercurial/robustcheckout.py
 chmod 644 /usr/local/mercurial/robustcheckout.py
 
 mkdir -p /etc/mercurial
 cat >/etc/mercurial/hgrc <<EOF
 # By default the progress bar starts after 3s and updates every 0.1s. We
 # change this so it shows and updates every 1.0s.
 # We also tell progress to assume a TTY is present so updates are printed
 # even if there is no known TTY.