Cleanup legacy codes related to plugins repo

Change-Id: Ia40b2dc9f2a5c59c415d83e30ed2726c3399808a
Bug: https://github.com/flutter/flutter/issues/122334
Reviewed-on: https://flutter-review.googlesource.com/c/recipes/+/46460
Commit-Queue: Keyong Han <keyonghan@google.com>
Reviewed-by: Ricardo Amador <ricardoamador@google.com>
diff --git a/recipe_modules/repo_util/api.py b/recipe_modules/repo_util/api.py
index 77d564f..b676d3a 100644
--- a/recipe_modules/repo_util/api.py
+++ b/recipe_modules/repo_util/api.py
@@ -12,7 +12,6 @@
     'monorepo': 'https://dart.googlesource.com/monorepo',
     'openpay': 'https://dash-internal.googlesource.com/openpay',
     'packages': 'https://flutter.googlesource.com/mirrors/packages',
-    'plugins': 'https://flutter.googlesource.com/mirrors/plugins',
 }
 
 # TODO(keyonghan): deprecate when all repos are migrated to main.
@@ -26,7 +25,6 @@
     'monorepo': 'main',
     'openpay': 'main',
     'packages': 'main',
-    'plugins': 'main',
 }
 
 import copy
diff --git a/recipe_modules/repo_util/examples/full.expected/monorepo_wrong_host.json b/recipe_modules/repo_util/examples/full.expected/monorepo_wrong_host.json
index 2d0d076..4ecade3 100644
--- a/recipe_modules/repo_util/examples/full.expected/monorepo_wrong_host.json
+++ b/recipe_modules/repo_util/examples/full.expected/monorepo_wrong_host.json
@@ -1144,7 +1144,7 @@
       "Traceback (most recent call last):",
       "  File \"RECIPE_REPO[flutter]/recipe_modules/repo_util/examples/full.py\", line 48, in RunSteps",
       "    api.repo_util.monorepo_checkout(checkout_path, {}, {})",
-      "  File \"RECIPE_REPO[flutter]/recipe_modules/repo_util/api.py\", line 177, in monorepo_checkout",
+      "  File \"RECIPE_REPO[flutter]/recipe_modules/repo_util/api.py\", line 175, in monorepo_checkout",
       "    raise ValueError(",
       "ValueError('Input reference is not on dart.googlesource.com/monorepo')"
     ]
diff --git a/recipe_modules/repo_util/examples/unsupported.expected/unsupported.json b/recipe_modules/repo_util/examples/unsupported.expected/unsupported.json
index 401eaef..cb630ab 100644
--- a/recipe_modules/repo_util/examples/unsupported.expected/unsupported.json
+++ b/recipe_modules/repo_util/examples/unsupported.expected/unsupported.json
@@ -9,7 +9,7 @@
       "Traceback (most recent call last):",
       "  File \"RECIPE_REPO[flutter]/recipe_modules/repo_util/examples/unsupported.py\", line 13, in RunSteps",
       "    api.repo_util.checkout('unsupported_repo', repo_dir)",
-      "  File \"RECIPE_REPO[flutter]/recipe_modules/repo_util/api.py\", line 254, in checkout",
+      "  File \"RECIPE_REPO[flutter]/recipe_modules/repo_util/api.py\", line 252, in checkout",
       "    raise ValueError('Unsupported repo: %s' % name)",
       "ValueError('Unsupported repo: unsupported_repo')"
     ]