Support breakpoints in deferred libraries

tests/standalone/debugger/deferred_code_test.dart

+// Copyright (c) 2014, 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.
+
+// Test to verify that a breakpoint can be set in code that is not yet
+// loaded, i.e. in a deferred library.
+//
+// This test forks a second vm process that runs this dart script as
+// a debug target.
+// Run this test with option --wire to see the json messages sent
+// between the processes.
+// Run this test with option --verbose to see the stdout and stderr output
+// of the debug target process.
+
+import "debug_lib.dart";
+import "deferred_code_lib.dart" deferred as D;
+
+
+main(List<String> arguments) {
+  if (RunScript(testScript, arguments)) return;
+  var loaded = false;
+  print("Hello from debuggee");
+  D.loadLibrary().then((_) {
+    loaded = true;
+    print("Done loading deferred library");
+    D.stopTheBuck();
+  });
+  print("main terminates");
+}
+
+
+// Expected debugger events and commands.
+var testScript = [
+  MatchFrame(0, "main"),  // Top frame in trace is function "main".
+  SetBreakpoint(22),  // Breakpoint just before call to loadLibrary().
+  Resume(),
+  // Set BP in deferred library code before the loadLibrary() call is executed.
+  MatchFrame(0, "main"),
+  MatchLine(22),
+  MatchLocals({"loaded": "false"}),
+  SetBreakpoint(10, url: "deferred_code_lib.dart"),
+  Resume(),
+  MatchFrame(0, "stopTheBuck"),  // Expect to be stopped in deferred library code.
+  // MatchLine(10), // Line matching only works for the main script.
+  Resume(),
+];