Initial version of completion plugin API

pkg/analysis_server/lib/completion/completion_dart.dart

+// Copyright (c) 2015, 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.
+
+library analysis_server.completion.completion_dart;
+
+import 'package:analysis_server/completion/completion_core.dart';
+import 'package:analyzer/src/generated/ast.dart';
+
+abstract class DartCompletionContributor extends CompletionContributor {
+  @override
+  CompletionResult computeSuggestions(CompletionRequest request) {
+    // TODO(brianwilkerson) Implement this by getting the information required
+    // to create a DartCompletionRequest and calling:
+    // return internalComputeSuggestions(dartRequest);
+    return null;
+  }
+
+  /**
+   * Compute a list of completion suggestions based on the given completion
+   * [request] and return a result that includes those suggestions. This method
+   * is called after specific phases of analysis until the contributor indicates
+   * computation is complete by setting [CompletionResult.isLast] to `true`.
+   */
+  CompletionResult internalComputeSuggestions(DartCompletionRequest request);
+}
+
+/**
+ * The information about a requested list of completions within a Dart file.
+ */
+abstract class DartCompletionRequest extends CompletionRequest {
+  /**
+   * Return `true` if the compilation [unit] is resolved.
+   */
+  bool get isResolved;
+
+  /**
+   * The compilation unit in which the completion was requested.
+   */
+  CompilationUnit get unit;
+
+  /**
+   * Cached information from a prior code completion operation.
+   */
+  //DartCompletionCache get cache;
+
+  /**
+   * The completion target.  This determines what part of the parse tree
+   * will receive the newly inserted text.
+   */
+  //CompletionTarget get target;
+
+  /**
+   * Information about the types of suggestions that should be included.
+   */
+  //OpType get _optype;
+}