[Fuchsia] Remove the legacy tools/fuchsia/target_api_level file

DEPS

@@ -289,7 +289,7 @@ allowed_hosts = [
 ]
 
 deps = {
-  'src': 'https://github.com/flutter/buildroot.git' + '@' + 'a22a4ea15e0b9cbba9200014f90fcea16ecb896a',
+  'src': 'https://github.com/flutter/buildroot.git' + '@' + 'bce07474ce354afc8ea6bb1b695cc86ef376260d',
 
   'src/flutter/third_party/depot_tools':
   Var('chromium_git') + '/chromium/tools/depot_tools.git' + '@' + '580b4ff3f5cd0dcaa2eacda28cefe0f45320e8f7',

ci/builders/linux_fuchsia.json

@@ -405,6 +405,10 @@
                     "name": "run_tests test",
                     "script": "flutter/testing/fuchsia/run_tests_test.py"
                 },
+                {
+                    "name": "build_fuchsia_artifacts test",
+                    "script": "flutter/tools/fuchsia/build_fuchsia_artifacts_test.py"
+                },
                 {
                     "name": "x64 emulator based debug tests",
                     "language": "python3",

tools/fuchsia/build_fuchsia_artifacts.py

@@ -178,10 +178,12 @@ def CopyToBucket(src, dst, product=False):
 
 
 def ReadTargetAPILevel():
-  filename = os.path.join(os.path.dirname(__file__), 'target_api_level')
+  filename = os.path.join(os.path.dirname(__file__), '../../build/config/fuchsia/gn_configs.gni')
   with open(filename) as f:
-    api_level = f.read().rstrip('\n')
-  return api_level
+    for line in f:
+      if line.startswith('fuchsia_target_api_level'):
+        return line.split('=')[-1].strip()
+  assert False, 'No fuchsia_target_api_level found in //flutter/build/config/fuchsia/gn_configs.gni'
 
 
 def CopyVulkanDepsToBucket(src, dst, arch):

tools/fuchsia/build_fuchsia_artifacts_test.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env vpython3
+
+import unittest
+
+import build_fuchsia_artifacts
+
+
+class BuildFuchsiaArtifactsTest(unittest.TestCase):
+
+  def test_read_fuchsia_target_api_level(self):
+    # It's expected to update this test each time the fuchsia_target_api_level
+    # in //flutter/build/config/fuchsia/gn_configs.gni is changed, so it won't
+    # accidentally publishing the artifacts with a wrong api level suffix.
+    self.assertEqual(build_fuchsia_artifacts.ReadTargetAPILevel(), '16')
+
+
+if __name__ == '__main__':
+  unittest.main()

tools/gn

@@ -768,12 +768,6 @@ def to_gn_args(args):
   if args.target_os == 'fuchsia':
     gn_args['gn_configs_path'] = '//flutter/build/config/fuchsia/gn_configs.gni'
     gn_args['fuchsia_gn_sdk'] = '//flutter/tools/fuchsia/gn-sdk'
-  if args.fuchsia_target_api_level is not None:
-    gn_args['fuchsia_target_api_level'] = args.fuchsia_target_api_level
-  elif args.target_os == 'fuchsia':
-    # Read the default target api level from a file so we can update it with a roller
-    with open(os.path.join(os.path.dirname(__file__), 'fuchsia/target_api_level')) as file:
-      gn_args['fuchsia_target_api_level'] = int(file.read().strip())
 
   # Flags for Dart features:
   if args.use_mallinfo2:
@@ -1222,8 +1216,6 @@ def parse_args(args):
   )
   parser.add_argument('--no-prebuilt-dart-sdk', dest='prebuilt_dart_sdk', action='store_false')
 
-  parser.add_argument('--fuchsia-target-api-level', dest='fuchsia_target_api_level')
-
   # Flags for Dart features.
   parser.add_argument(
       '--use-mallinfo2',