Add script to test impeller-cmake-example (flutter/engine#41133)

This PR adds an engine CI configuration that downloads the
impeller-cmake-example and builds it.

engine/src/flutter/.ci.yaml

@@ -444,6 +444,21 @@ targets:
           {"dependency": "jazzy", "version": "0.14.1"}
         ]
 
+  - name: Mac impeller-cmake-example
+    bringup: true
+    recipe: engine_v2/engine_v2
+    timeout: 60
+    properties:
+      release_build: "true"
+      config_name: impeller_cmake_build_test
+      $flutter/osx_sdk : >-
+        { "sdk_version": "14a5294e" }
+      dependencies: >-
+        [
+          {"dependency": "cmake", "version": "build_id:8784715802296535313"},
+          {"dependency": "jazzy", "version": "0.14.1"}
+        ]
+
   - name: Windows Android AOT Engine
     recipe: engine/engine
     properties:

engine/src/flutter/ci/builders/mac_impeller_cmake_example.json

@@ -0,0 +1,38 @@
+{
+    "builds": [
+        {
+            "name": "impeller_cmake_build_test",
+            "archives": [],
+            "drone_dimensions": [
+                "device_type=none",
+                "os=Mac-12",
+                "cpu=x86"
+            ],
+            "gclient_custom_vars": {
+                "download_android_deps": false,
+                "download_impeller_cmake_example": true
+            },
+            "tests": [
+                {
+                    "language": "python3",
+                    "name": "cmake",
+                    "script": "flutter/ci/impeller_cmake_build_test.py",
+                    "parameters": [
+                        "--cmake"
+                    ],
+                    "type": "local"
+                },
+                {
+                    "language": "python3",
+                    "name": "build",
+                    "script": "flutter/ci/impeller_cmake_build_test.py",
+                    "parameters": [
+                        "--build"
+                    ],
+                    "type": "local"
+                }
+            ]
+        }
+    ],
+    "tests": []
+}

engine/src/flutter/ci/impeller_cmake_build_test.py

@@ -0,0 +1,163 @@
+#!/usr/bin/env vpython3
+# 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.
+
+import argparse
+import os
+import subprocess
+import sys
+
+SRC_ROOT = os.path.dirname(
+    os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+)
+
+
+def parse_args(argv):
+  parser = argparse.ArgumentParser(
+      description='A script that tests the impeller-cmake-example build.',
+  )
+  parser.add_argument(
+      '--build',
+      '-b',
+      default=False,
+      action='store_true',
+      help='Perform the build for impeller-cmake-example.',
+  )
+  parser.add_argument(
+      '--cmake',
+      '-c',
+      default=False,
+      action='store_true',
+      help='Run cmake for impeller-cmake-example.',
+  )
+  parser.add_argument(
+      '--goma-dir',
+      '-g',
+      type=str,
+      default=os.getenv('GOMA_DIR'),
+      help=(
+          'The path to the Goma install. Defaults to the value of the '
+          'GOMA_DIR environment variable.'
+      ),
+  )
+  parser.add_argument(
+      '--path',
+      '-p',
+      type=str,
+      help='The path to the impeller-cmake-example source.',
+  )
+  parser.add_argument(
+      '--setup',
+      '-s',
+      default=False,
+      action='store_true',
+      help='Clone the git submodules.',
+  )
+  parser.add_argument(
+      '--verbose',
+      '-v',
+      default=False,
+      action='store_true',
+      help='Emit verbose output.',
+  )
+  parser.add_argument(
+      '--xcode-symlink',
+      default=False,
+      action='store_true',
+      help='Symlink the Xcode sysroot to help Goma be successful.',
+  )
+  return parser.parse_args(argv)
+
+
+def validate_args(args):
+  if not os.path.isdir(os.path.join(SRC_ROOT, args.path)):
+    print(
+        'The --path argument must be a valid directory relative to the '
+        'engine src/ directory.'
+    )
+    return False
+
+  return True
+
+
+def create_xcode_symlink():
+  find_sdk_command = [
+      'python3',
+      os.path.join(SRC_ROOT, 'build', 'mac', 'find_sdk.py'),
+      '--print_sdk_path',
+      '10.15',
+      '--symlink',
+      os.path.join(SRC_ROOT, 'out', 'impeller-cmake-example-xcode-sysroot'),
+  ]
+  find_sdk_output = subprocess.check_output(find_sdk_command).decode('utf-8')
+  print(find_sdk_output)
+  sysroot_path = find_sdk_output.split('\n')[0]
+  print('sysroot path = {}'.format(sysroot_path))
+  return sysroot_path
+
+
+def main(argv):
+  args = parse_args(argv[1:])
+  if not validate_args(args):
+    return 1
+
+  impeller_cmake_dir = os.path.join(SRC_ROOT, args.path)
+
+  if args.setup:
+    print('git submodule update with {} jobs'.format(str(os.cpu_count())))
+    git_command = [
+        'git',
+        '-C',
+        impeller_cmake_dir,
+        'submodule',
+        'update',
+        '--init',
+        '--recursive',
+        # '--single-branch',
+        '--depth',
+        '1',
+        '--jobs',
+        str(os.cpu_count()),
+    ]
+    subprocess.check_call(git_command)
+
+    # Run the deps.sh shell script in the repo.
+    subprocess.check_call(['bash', 'deps.sh'], cwd=impeller_cmake_dir)
+    return 0
+
+  if args.cmake:
+    cmake_command = [
+        'cmake',
+        '--preset',
+        'flutter-ci-mac-debug-x64',
+        '-B',
+        os.path.join(SRC_ROOT, 'out', 'impeller-cmake-example-out'),
+    ]
+    cmake_env = os.environ.copy()
+    cmake_env.update({
+        'FLUTTER_ENGINE_SRC_DIR': SRC_ROOT,
+        'FLUTTER_GOMA_DIR': args.goma_dir,
+    })
+    if args.xcode_symlink:
+      xcode_symlink_path = create_xcode_symlink()
+      cmake_env.update({
+          'FLUTTER_OSX_SYSROOT': xcode_symlink_path,
+      })
+    subprocess.check_call(cmake_command, env=cmake_env, cwd=impeller_cmake_dir)
+
+  if args.build:
+    ninja_command = [
+        'ninja',
+        '-C',
+        os.path.join(SRC_ROOT, 'out', 'impeller-cmake-example-out'),
+        '-j',
+        '200',
+    ]
+    subprocess.check_call(ninja_command)
+
+  return 0
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv))