Add a --no-precompile flag.

test/snapshot/no_precompile_test.dart

+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:path/path.dart' as p;
+import 'package:scheduled_test/scheduled_test.dart';
+
+import '../descriptor.dart' as d;
+import '../test_pub.dart';
+
+main() {
+  group("with --no-precompile,", () {
+    integration("doesn't create a new snapshot", () {
+      servePackages((builder) {
+        builder.serve("foo", "1.2.3", contents: [
+          d.dir("bin", [
+            d.file("hello.dart", "void main() => print('hello!');"),
+            d.file("goodbye.dart", "void main() => print('goodbye!');"),
+            d.file("shell.sh", "echo shell"),
+            d.dir("subdir", [
+              d.file("sub.dart", "void main() => print('sub!');")
+            ])
+          ])
+        ]);
+      });
+
+      d.appDir({"foo": "1.2.3"}).create();
+
+      pubGet(args: ["--no-precompile"], output: isNot(contains("Precompiled")));
+
+      d.nothing(p.join(appPath, '.pub')).validate();
+
+      var process = pubRun(args: ['foo:hello']);
+      process.stdout.expect("hello!");
+      process.shouldExit();
+
+      process = pubRun(args: ['foo:goodbye']);
+      process.stdout.expect("goodbye!");
+      process.shouldExit();
+    });
+
+    integration("deletes a snapshot when its package is upgraded", () {
+      servePackages((builder) {
+        builder.serve("foo", "1.2.3", contents: [
+          d.dir("bin", [
+            d.file("hello.dart", "void main() => print('hello!');")
+          ])
+        ]);
+      });
+
+      d.appDir({"foo": "any"}).create();
+
+      pubGet(output: contains("Precompiled foo:hello."));
+
+      d.dir(p.join(appPath, '.pub', 'bin', 'foo'), [
+        d.matcherFile('hello.dart.snapshot', contains('hello!'))
+      ]).validate();
+
+      globalPackageServer.add((builder) {
+        builder.serve("foo", "1.2.4", contents: [
+          d.dir("bin", [
+            d.file("hello.dart", "void main() => print('hello 2!');")
+          ])
+        ]);
+      });
+
+      pubUpgrade(
+          args: ["--no-precompile"],
+          output: isNot(contains("Precompiled")));
+
+      d.nothing(p.join(appPath, '.pub', 'bin', 'foo')).validate();
+
+      var process = pubRun(args: ['foo:hello']);
+      process.stdout.expect("hello 2!");
+      process.shouldExit();
+    });
+
+    integration("doesn't delete a snapshot when no dependencies of a package "
+        "have changed", () {
+      servePackages((builder) {
+        builder.serve("foo", "1.2.3", deps: {"bar": "any"}, contents: [
+          d.dir("bin", [
+            d.file("hello.dart", "void main() => print('hello!');")
+          ])
+        ]);
+        builder.serve("bar", "1.2.3");
+      });
+
+      d.appDir({"foo": "1.2.3"}).create();
+
+      pubGet(output: contains("Precompiled foo:hello."));
+
+      pubUpgrade(
+          args: ["--no-precompile"],
+          output: isNot(contains("Precompiled")));
+
+      d.dir(p.join(appPath, '.pub', 'bin'), [
+        d.file('sdk-version', '0.1.2+3\n'),
+        d.dir('foo', [d.matcherFile('hello.dart.snapshot', contains('hello!'))])
+      ]).validate();
+    });
+  });
+}