Add format API

editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/FormatConsumer.java

Index: editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/FormatConsumer.java
diff --git a/editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/FormatConsumer.java b/editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/FormatConsumer.java
new file mode 100644
index 0000000000000000000000000000000000000000..1a60d2b680fd48a3686c2e792b2069e2588d1a2f
--- /dev/null
+++ b/editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/FormatConsumer.java
@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2015, the Dart project authors.
+ * 
+ * Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ * 
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.google.dart.server;
+
+import com.google.dart.server.generated.types.RequestError;
+import com.google.dart.server.generated.types.SourceEdit;
+
+import java.util.List;
+
+/**
+ * The interface {@code FormatConsumer} defines the behavior of objects that consume the results of
+ * an {@code edit.format} request.
+ */
+public interface FormatConsumer extends Consumer {
+  /**
+   * The result of formatting code has been computed.
+   * 
+   * @param edits the edit(s) to be applied in order to format the code. The list will be empty if
+   *          the code was already formatted (there are no changes).
+   * @param selectionOffset the offset of the selection after formatting the code
+   * @param selectionLength the length of the selection after formatting the code
+   */
+  public void computedFormat(List<SourceEdit> edits, int selectionOffset, int selectionLength);
+
+  /**
+   * If a formatting edits cannot be passed back, some {@link RequestError} is passed back instead.
+   * 
+   * @param requestError the reason why a result was not passed back
+   */
+  public void onError(RequestError requestError);
+}