chore: Prepare Dockerfile for Recaptcha tests (#9177)

Author: rsamborski

.kokoro/docker/Dockerfile

@@ -202,4 +202,21 @@ RUN useradd -d /h -u ${UID} ${USERNAME}
 # Allow nopasswd sudo
 RUN echo "${USERNAME} ALL=(ALL) NOPASSWD:ALL" >> /etc/sudoers
 
+# Install Chrome.
+RUN curl https://dl-ssl.google.com/linux/linux_signing_key.pub -o /tmp/google.pub \
+  && cat /tmp/google.pub | apt-key add -; rm /tmp/google.pub \
+  && echo 'deb http://dl.google.com/linux/chrome/deb/ stable main' > /etc/apt/sources.list.d/google.list \
+  && mkdir -p /usr/share/desktop-directories \
+  && apt-get -y update && apt-get install -y google-chrome-stable
+
+# Disable the SUID sandbox so that Chrome can launch without being in a privileged container.
+RUN dpkg-divert --add --rename --divert /opt/google/chrome/google-chrome.real /opt/google/chrome/google-chrome \
+  && echo "#!/bin/bash\nexec /opt/google/chrome/google-chrome.real --no-sandbox --disable-setuid-sandbox \"\$@\"" > /opt/google/chrome/google-chrome \
+  && chmod 755 /opt/google/chrome/google-chrome
+
+# Install Chrome Driver.
+RUN mkdir -p /opt/selenium \
+  && curl http://chromedriver.storage.googleapis.com/`curl -sS chromedriver.storage.googleapis.com/LATEST_RELEASE`/chromedriver_linux64.zip -o /opt/selenium/chromedriver_linux64.zip \
+  && cd /opt/selenium; unzip /opt/selenium/chromedriver_linux64.zip; rm -rf chromedriver_linux64.zip; ln -fs /opt/selenium/chromedriver /usr/local/bin/chromedriver;
+
 CMD ["python3"]