Initial experimental Kythe Dart Analysis Server protocol

R=brianwilkerson@google.com

Review-Url: https://codereview.chromium.org/2995683002 .

pkg/analysis_server/tool/spec/generated/java/AnalysisServer.java

@@ -631,6 +631,16 @@ public interface AnalysisServer {
    */
   public boolean isSocketOpen();
 
+  /**
+   * {@code kythe.getKytheEntries}
+   *
+   * Return the list of KytheEntry objects for some file, given the current state of the file system
+   * populated by "analysis.updateContent".
+   *
+   * @param file The file containing the code for which the Kythe Entry objects are being requested.
+   */
+  public void kythe_getKytheEntries(String file, GetKytheEntriesConsumer consumer);
+
   /**
    * Remove the given listener from the list of listeners that will receive notification when new
      * analysis results become available.