[flutter_tools] remove dependencies checks that are no longer relevant in assemble-land (#50225)

diff --git a/packages/flutter_tools/lib/src/base/build.dart b/packages/flutter_tools/lib/src/base/build.dart
index 370e750..940f4e6 100644
--- a/packages/flutter_tools/lib/src/base/build.dart
+++ b/packages/flutter_tools/lib/src/base/build.dart
@@ -10,7 +10,6 @@
 import '../build_info.dart';
 import '../bundle.dart';
 import '../compile.dart';
-import '../dart/package_map.dart';
 import '../globals.dart' as globals;
 import '../macos/xcode.dart';
 import '../project.dart';
@@ -109,22 +108,9 @@
     // TODO(cbracken): replace IOSArch with TargetPlatform.ios_{armv7,arm64}.
     assert(platform != TargetPlatform.ios || darwinArch != null);
 
-    final PackageMap packageMap = PackageMap(packagesPath);
-    final String packageMapError = packageMap.checkValid();
-    if (packageMapError != null) {
-      globals.printError(packageMapError);
-      return 1;
-    }
-
     final Directory outputDir = globals.fs.directory(outputPath);
     outputDir.createSync(recursive: true);
 
-    final String skyEnginePkg = _getPackagePath(packageMap, 'sky_engine');
-    final String uiPath = globals.fs.path.join(skyEnginePkg, 'lib', 'ui', 'ui.dart');
-    final String vmServicePath = globals.fs.path.join(skyEnginePkg, 'sdk_ext', 'vmservice_io.dart');
-
-    final List<String> inputPaths = <String>[uiPath, vmServicePath, mainPath];
-    final Set<String> outputPaths = <String>{};
     final List<String> genSnapshotArgs = <String>[
       '--deterministic',
     ];
@@ -136,13 +122,11 @@
     final String assembly = globals.fs.path.join(outputDir.path, 'snapshot_assembly.S');
     if (platform == TargetPlatform.ios || platform == TargetPlatform.darwin_x64) {
       // Assembly AOT snapshot.
-      outputPaths.add(assembly);
       genSnapshotArgs.add('--snapshot_kind=app-aot-assembly');
       genSnapshotArgs.add('--assembly=$assembly');
       genSnapshotArgs.add('--strip');
     } else {
       final String aotSharedLibrary = globals.fs.path.join(outputDir.path, 'app.so');
-      outputPaths.add(aotSharedLibrary);
       genSnapshotArgs.add('--snapshot_kind=app-aot-elf');
       genSnapshotArgs.add('--elf=$aotSharedLibrary');
       genSnapshotArgs.add('--strip');
@@ -181,13 +165,6 @@
 
     genSnapshotArgs.add(mainPath);
 
-    // TODO(jonahwilliams): fully remove input checks once all callers are
-    // using assemble.
-    final Iterable<String> missingInputs = inputPaths.where((String p) => !globals.fs.isFileSync(p));
-    if (missingInputs.isNotEmpty) {
-      globals.printTrace('Missing input files: $missingInputs from $inputPaths');
-    }
-
     final SnapshotType snapshotType = SnapshotType(platform, buildMode);
     final int genSnapshotExitCode =
       await _timedStep('snapshot(CompileTime)', 'aot-snapshot',
@@ -201,12 +178,6 @@
       return genSnapshotExitCode;
     }
 
-    // Write path to gen_snapshot, since snapshots have to be re-generated when we roll
-    // the Dart SDK.
-    // TODO(jonahwilliams): remove when all callers are using assemble.
-    final String genSnapshotPath = GenSnapshot.getSnapshotterPath(snapshotType);
-    outputDir.childFile('gen_snapshot.d').writeAsStringSync('gen_snapshot.d: $genSnapshotPath\n');
-
     // On iOS and macOS, we use Xcode to compile the snapshot into a dynamic library that the
     // end-developer can link into their app.
     if (platform == TargetPlatform.ios || platform == TargetPlatform.darwin_x64) {
@@ -354,10 +325,6 @@
     ].contains(platform);
   }
 
-  String _getPackagePath(PackageMap packageMap, String package) {
-    return globals.fs.path.dirname(globals.fs.path.fromUri(packageMap.map[package]));
-  }
-
   /// This method is used to measure duration of an action and emit it into
   /// verbose output from flutter_tool for other tools (e.g. benchmark runner)
   /// to find.
diff --git a/packages/flutter_tools/test/general.shard/build_system/targets/dart_test.dart b/packages/flutter_tools/test/general.shard/build_system/targets/dart_test.dart
index 590887d..1afc129 100644
--- a/packages/flutter_tools/test/general.shard/build_system/targets/dart_test.dart
+++ b/packages/flutter_tools/test/general.shard/build_system/targets/dart_test.dart
@@ -63,22 +63,10 @@
       } else {
         assert(false);
       }
-      final String skyEngineLine = globals.platform.isWindows
-        ? r'sky_engine:file:///C:/bin/cache/pkg/sky_engine/lib/'
-        : 'sky_engine:file:///bin/cache/pkg/sky_engine/lib/';
-      globals.fs.file('.packages')
-        ..createSync()
-        ..writeAsStringSync('''
-# Generated
-$skyEngineLine
-flutter_tools:lib/''');
+
       final String engineArtifacts = globals.fs.path.join('bin', 'cache',
           'artifacts', 'engine');
       final List<String> paths = <String>[
-        globals.fs.path.join('bin', 'cache', 'pkg', 'sky_engine', 'lib', 'ui',
-          'ui.dart'),
-        globals.fs.path.join('bin', 'cache', 'pkg', 'sky_engine', 'sdk_ext',
-            'vmservice_io.dart'),
         globals.fs.path.join('bin', 'cache', 'dart-sdk', 'bin', 'dart'),
         globals.fs.path.join('bin', 'cache', 'dart-sdk', 'bin', 'dart.exe'),
         globals.fs.path.join(engineArtifacts, getNameForHostPlatform(hostPlatform),