Add logging to the incremental resolver.

pkg/analysis_server/lib/src/analysis_server.dart

Index: pkg/analysis_server/lib/src/analysis_server.dart
diff --git a/pkg/analysis_server/lib/src/analysis_server.dart b/pkg/analysis_server/lib/src/analysis_server.dart
index c34668222e6564b1097ec87e08f2241293031570..f5a4e1afe872a5bc043f05b05d1d4d63d3f34ca7 100644
--- a/pkg/analysis_server/lib/src/analysis_server.dart
+++ b/pkg/analysis_server/lib/src/analysis_server.dart
@@ -192,6 +192,8 @@ class AnalysisServer {
         new ServerContextManager(this, resourceProvider, packageMapProvider);
     contextDirectoryManager.defaultOptions.incremental =
         analysisServerOptions.enableIncrementalResolution;
+    contextDirectoryManager.defaultOptions.incrementalLog =
+        analysisServerOptions.incrementalResolutionLog;
     AnalysisEngine.instance.logger = new AnalysisLogger();
     _onAnalysisStartedController = new StreamController.broadcast();
     _onAnalysisCompleteController = new StreamController.broadcast();
@@ -918,6 +920,7 @@ class AnalysisServer {
 
 class AnalysisServerOptions {
   bool enableIncrementalResolution = false;
+  String incrementalResolutionLog = null;
 }
 
 /**