Suppress a few analysis warnings in the analyzer codebase.

pkg/analyzer_plugin/lib/plugin/plugin.dart

Index: pkg/analyzer_plugin/lib/plugin/plugin.dart
diff --git a/pkg/analyzer_plugin/lib/plugin/plugin.dart b/pkg/analyzer_plugin/lib/plugin/plugin.dart
index f24f6b811c71626d181b02464995658c5f77d837..f7393442855911be0577b97b8680068f12772826 100644
--- a/pkg/analyzer_plugin/lib/plugin/plugin.dart
+++ b/pkg/analyzer_plugin/lib/plugin/plugin.dart
@@ -63,7 +63,7 @@ abstract class ServerPlugin {
    * the cache location isn't known because the 'plugin.version' request has not
    * yet been received.
    */
-  ByteStore _byteStore;
+  ByteStore _byteStore; // ignore: unused_field

[scheglov, 2017/02/10 21:06:53]

I think Brian will use it eventually, and again, I think it's OK to keep it
visible so that we don't hide and forget about it.

[devoncarew, 2017/02/10 21:12:35]

Removed the ignore.

 
   /**
    * The file content overlay used by any analysis drivers that are created.