Don't load transformers that aren't going to be used for an executable.

sdk/lib/_internal/pub_generated/test/dependency_computer/transformers_needed_by_library_test.dart

Index: sdk/lib/_internal/pub_generated/test/dependency_computer/transformers_needed_by_library_test.dart
diff --git a/sdk/lib/_internal/pub_generated/test/dependency_computer/transformers_needed_by_library_test.dart b/sdk/lib/_internal/pub_generated/test/dependency_computer/transformers_needed_by_library_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..be6094534d62d779e59b58defd66df19e9ef85e4
--- /dev/null
+++ b/sdk/lib/_internal/pub_generated/test/dependency_computer/transformers_needed_by_library_test.dart
@@ -0,0 +1,111 @@
+library pub_tests;
+import '../descriptor.dart' as d;
+import '../test_pub.dart';
+import 'utils.dart';
+void main() {
+  initConfig();
+  integration("reports a dependency if the library itself is transformed", () {
+    d.dir(appPath, [d.pubspec({
+        "name": "myapp",
+        "dependencies": {
+          "foo": {
+            "path": "../foo"
+          }
+        },
+        "transformers": [{
+            "foo": {
+              "\$include": "bin/myapp.dart.dart"
+            }
+          }]
+      }),
+          d.dir(
+              "bin",
+              [d.file("myapp.dart", "import 'package:myapp/lib.dart';")])]).create();
+    d.dir("foo", [d.pubspec({
+        "name": "foo",
+        "version": "1.0.0"
+      }), d.dir("lib", [d.file("foo.dart", transformer())])]).create();
+    expectLibraryDependencies('myapp|bin/myapp.dart', ['foo']);
+  });
+  integration(
+      "reports a dependency if a transformed local file is imported",
+      () {
+    d.dir(appPath, [d.pubspec({
+        "name": "myapp",
+        "dependencies": {
+          "foo": {
+            "path": "../foo"
+          }
+        },
+        "transformers": [{
+            "foo": {
+              "\$include": "lib/lib.dart"
+            }
+          }]
+      }),
+          d.dir("lib", [d.file("lib.dart", "")]),
+          d.dir(
+              "bin",
+              [d.file("myapp.dart", "import 'package:myapp/lib.dart';")])]).create();
+    d.dir("foo", [d.pubspec({
+        "name": "foo",
+        "version": "1.0.0"
+      }), d.dir("lib", [d.file("foo.dart", transformer())])]).create();
+    expectLibraryDependencies('myapp|bin/myapp.dart', ['foo']);
+  });
+  integration(
+      "reports a dependency if a transformed foreign file is imported",
+      () {
+    d.dir(appPath, [d.pubspec({
+        "name": "myapp",
+        "dependencies": {
+          "foo": {
+            "path": "../foo"
+          }
+        }
+      }),
+          d.dir(
+              "bin",
+              [d.file("myapp.dart", "import 'package:foo/foo.dart';")])]).create();
+    d.dir("foo", [d.pubspec({
+        "name": "foo",
+        "version": "1.0.0",
+        "transformers": [{
+            "foo": {
+              "\$include": "lib/foo.dart"
+            }
+          }]
+      }),
+          d.dir(
+              "lib",
+              [d.file("foo.dart", ""), d.file("transformer.dart", transformer())])]).create();
+    expectLibraryDependencies('myapp|bin/myapp.dart', ['foo']);
+  });
+  integration(
+      "doesn't report a dependency if no transformed files are " "imported",
+      () {
+    d.dir(appPath, [d.pubspec({
+        "name": "myapp",
+        "dependencies": {
+          "foo": {
+            "path": "../foo"
+          }
+        },
+        "transformers": [{
+            "foo": {
+              "\$include": "lib/lib.dart"
+            }
+          }]
+      }),
+          d.dir("lib", [d.file("lib.dart", ""), d.file("untransformed.dart", "")]),
+          d.dir(
+              "bin",
+              [
+                  d.file("myapp.dart", "import 'package:myapp/untransformed.dart';")])]).create();
+    d.dir("foo", [d.pubspec({
+        "name": "foo",
+        "version": "1.0.0"
+      }), d.dir("lib", [d.file("foo.dart", transformer())])]).create();
+    expectLibraryDependencies('myapp|bin/myapp.dart', []);
+  });
+}