perf(dart/transform) Restructure transform to independent phases

Update summary:
- Removes the need for resolution, gaining transform speed at the cost
  of some precision and ability to detect errors
- Generates type registrations in the package alongside their declarations
- Ensures that line numbers do not change in transformed user code

modules/angular2/src/transform/reflection_remover/codegen.dart

@@ -0,0 +1,89 @@
+library angular2.src.transform.reflection_remover.codegen;
+
+import 'package:analyzer/src/generated/ast.dart';
+import 'package:barback/barback.dart';
+import 'package:code_transformers/resolver.dart';
+import 'package:path/path.dart' as path;
+
+import 'package:angular2/src/transform/common/names.dart';
+
+class Codegen {
+  static const _PREFIX_BASE = 'ngStaticInit';
+
+  /// The prefix used to import our generated file.
+  final String prefix;
+  /// The import uri
+  final String importUri;
+
+  Codegen(String reflectionEntryPointPath, String newEntryPointPath,
+      {String prefix})
+      : this.prefix = prefix == null ? _PREFIX_BASE : prefix,
+        importUri = path.relative(newEntryPointPath,
+            from: path.dirname(reflectionEntryPointPath)) {
+    if (this.prefix.isEmpty) throw new ArgumentError.value('(empty)', 'prefix');
+  }
+
+  factory Codegen.fromResolver(
+      Resolver resolver, AssetId reflectionEntryPoint, AssetId newEntryPoint) {
+    var lib = resolver.getLibrary(reflectionEntryPoint);
+    var prefix = _PREFIX_BASE;
+    var idx = 0;
+    while (lib.imports.any((import) {
+      return import.prefix != null && import.prefix == prefix;
+    })) {
+      prefix = '${_PREFIX_BASE}${idx++}';
+    }
+
+    return new Codegen(reflectionEntryPoint, newEntryPoint, prefix: prefix);
+  }
+
+  /// Generates code to import the library containing the method which sets up
+  /// Angular2 reflection statically.
+  ///
+  /// The code generated here should follow the example of code generated for
+  /// an [ImportDirective] node.
+  String codegenImport() {
+    return 'import \'${importUri}\' as ${prefix};';
+  }
+
+  /// Generates code to call the method which sets up Angular2 reflection
+  /// statically.
+  ///
+  /// If [reflectorAssignment] is provided, it is expected to be the node
+  /// representing the [ReflectionCapabilities] assignment, and we will
+  /// attempt to parse the access of [reflector] from it so that [reflector] is
+  /// properly prefixed if necessary.
+  String codegenSetupReflectionCall(
+      {AssignmentExpression reflectorAssignment}) {
+    var reflectorExpression = null;
+    if (reflectorAssignment != null) {
+      reflectorExpression = reflectorAssignment.accept(new _ReflectorVisitor());
+    }
+    if (reflectorExpression == null) {
+      reflectorExpression = 'reflector';
+    }
+
+    return '${prefix}.${SETUP_METHOD_NAME}(${reflectorExpression});';
+  }
+}
+
+/// A visitor whose job it is to find the access of [reflector].
+class _ReflectorVisitor extends Object with SimpleAstVisitor<Expression> {
+  @override
+  Expression visitAssignmentExpression(AssignmentExpression node) {
+    if (node == null || node.leftHandSide == null) return null;
+    return node.leftHandSide.accept(this);
+  }
+
+  @override
+  Expression visitPropertyAccess(PropertyAccess node) {
+    if (node == null || node.target == null) return;
+    return node.target;
+  }
+
+  @override
+  Expression visitPrefixedIdentifier(PrefixedIdentifier node) {
+    if (node == null || node.prefix == null) return null;
+    return node.prefix;
+  }
+}