Handle null content in ContentChange.

pkg/analysis_server/lib/src/protocol.dart

Index: pkg/analysis_server/lib/src/protocol.dart
diff --git a/pkg/analysis_server/lib/src/protocol.dart b/pkg/analysis_server/lib/src/protocol.dart
index fddf7d2a8cfe89d628ad34bb3b2e6f9aea8cf60a..85a762de026ce9d05552e8017357754a8d9e83a9 100644
--- a/pkg/analysis_server/lib/src/protocol.dart
+++ b/pkg/analysis_server/lib/src/protocol.dart
@@ -401,6 +401,8 @@ class RequestDatum {
     }
     return datum;
   }
+
+  bool get isNull => datum == null;

[scheglov, 2014/06/13 16:55:53]

Should we add a documentation for it?

[Paul Berry, 2014/06/13 20:23:00]

I couldn't think of a documentation comment that wasn't so obvious that it
looked silly, e.g.:

/**
 * True if the datum is null.
 */
bool get isNull => datum == null;

I'm open to suggestions.

 }
 
 /**