[ci] Remove unused Chromium setup (#4437)

The tasks that used the Cirrus template and shell script to install a specific version of Chromium have been migrated to LUCI, so this is cruft; I forgot to remove it when finishing that migration.

Also combines two setup steps into one template now that they are only used together.

.cirrus.yml

@@ -6,23 +6,7 @@ env:
   CHANNEL: "master" # Default to master when not explicitly set by a task.
   PLUGIN_TOOL_COMMAND: "dart ./script/tool/bin/flutter_plugin_tools.dart"
 
-install_chrome_linux_template: &INSTALL_CHROME_LINUX
-  env:
-    CHROME_NO_SANDBOX: true
-    CHROME_DOWNLOAD_DIR: /tmp/chromium
-    CHROME_EXECUTABLE: $CHROME_DOWNLOAD_DIR/chrome-linux/chrome
-    CHROMEDRIVER_EXECUTABLE: $CHROME_DOWNLOAD_DIR/chromedriver/chromedriver
-    PATH: $PATH:$CHROME_DOWNLOAD_DIR/chrome-linux
-  install_chromium_script:
-    # Install a pinned version of Chromium and its corresponding ChromeDriver.
-    # Setting CHROME_EXECUTABLE above causes this version to be used for tests.
-    - ./script/install_chromium.sh
-
-tool_setup_template: &TOOL_SETUP_TEMPLATE
-  tool_setup_script:
-    - .ci/scripts/prepare_tool.sh
-
-flutter_upgrade_template: &FLUTTER_UPGRADE_TEMPLATE
+setup_template: &SETUP_TEMPLATE
   upgrade_flutter_script:
     # Channels that are part of our normal test matrix use a pinned,
     # auto-rolled version to prevent out-of-band CI failures due to changes in
@@ -45,13 +29,14 @@ flutter_upgrade_template: &FLUTTER_UPGRADE_TEMPLATE
     - fi
     # Run doctor to allow auditing of what version of Flutter the run is using.
     - flutter doctor -v
-  << : *TOOL_SETUP_TEMPLATE
+  tool_setup_script:
+    - .ci/scripts/prepare_tool.sh
 
 # Light-workload Linux tasks.
 # These use default machines, with fewer CPUs, to reduce pressure on the
 # concurrency limits.
 task:
-  << : *FLUTTER_UPGRADE_TEMPLATE
+  << : *SETUP_TEMPLATE
   gke_container:
     dockerfile: .ci/Dockerfile
     builder_image_name: docker-builder-linux # gce vm image
@@ -129,7 +114,7 @@ task:
 # These use machines with more CPUs and memory, so will reduce parallelization
 # for non-credit runs.
 task:
-  << : *FLUTTER_UPGRADE_TEMPLATE
+  << : *SETUP_TEMPLATE
   gke_container:
     dockerfile: .ci/Dockerfile
     builder_image_name: docker-builder-linux # gce vm image

script/install_chromium.sh

@@ -1,54 +0,0 @@
-#!/bin/bash
-# Copyright 2013 The Flutter Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-# This script may be run as:
-# $ CHROME_DOWNLOAD_DIR=./whatever script/install_chromium.sh
-set -e
-set -x
-
-# The target directory where chromium is going to be downloaded
-: "${CHROME_DOWNLOAD_DIR:=/tmp/chromium}" # Default value for the CHROME_DOWNLOAD_DIR env.
-
-# The build of Chromium used to test web functionality.
-#
-# Chromium builds can be located here: https://commondatastorage.googleapis.com/chromium-browser-snapshots/index.html?prefix=Linux_x64/
-#
-# Check: https://github.com/flutter/engine/blob/master/lib/web_ui/dev/browser_lock.yaml
-: "${CHROMIUM_BUILD:=950363}" # Default value for the CHROMIUM_BUILD env.
-
-# Convenience defaults for CHROME_EXECUTABLE and CHROMEDRIVER_EXECUTABLE. These
-# two values should be set in the environment from CI, so this script can validate
-# that it has completed downloading chrome and driver successfully (and the expected
-# files are executable)
-: "${CHROME_EXECUTABLE:=$CHROME_DOWNLOAD_DIR/chrome-linux/chrome}"
-: "${CHROMEDRIVER_EXECUTABLE:=$CHROME_DOWNLOAD_DIR/chromedriver/chromedriver}"
-
-# The correct ChromeDriver is distributed alongside the chromium build above, as
-# `chromedriver_linux64.zip`, so no need to hardcode any extra info about it.
-readonly DOWNLOAD_ROOT="https://www.googleapis.com/download/storage/v1/b/chromium-browser-snapshots/o/Linux_x64%2F${CHROMIUM_BUILD}%2F"
-
-# Install Chromium.
-mkdir "$CHROME_DOWNLOAD_DIR"
-readonly CHROMIUM_ZIP_FILE="$CHROME_DOWNLOAD_DIR/chromium.zip"
-wget --no-verbose "${DOWNLOAD_ROOT}chrome-linux.zip?alt=media" -O "$CHROMIUM_ZIP_FILE"
-unzip -q "$CHROMIUM_ZIP_FILE" -d "$CHROME_DOWNLOAD_DIR/"
-
-# Install ChromeDriver.
-readonly DRIVER_ZIP_FILE="$CHROME_DOWNLOAD_DIR/chromedriver.zip"
-wget --no-verbose "${DOWNLOAD_ROOT}chromedriver_linux64.zip?alt=media" -O "$DRIVER_ZIP_FILE"
-unzip -q "$DRIVER_ZIP_FILE" -d "$CHROME_DOWNLOAD_DIR/"
-# Rename CHROME_DOWNLOAD_DIR/chromedriver_linux64 to the expected CHROME_DOWNLOAD_DIR/chromedriver
-mv -T "$CHROME_DOWNLOAD_DIR/chromedriver_linux64" "$CHROME_DOWNLOAD_DIR/chromedriver"
-
-# Echo info at the end for ease of debugging.
-#
-# exports from this script cannot be used elsewhere in the .cirrus.yml file.
-set +x
-echo
-echo "$CHROME_EXECUTABLE"
-"$CHROME_EXECUTABLE" --version
-echo "$CHROMEDRIVER_EXECUTABLE"
-"$CHROMEDRIVER_EXECUTABLE" --version
-echo