Canged CodedInputStream.ReadTag to use boolean result with out params to
support reading a field name rather than a field tag.
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestImportProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestImportProtoFile.cs
index 309dfc6..d97466d 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestImportProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestImportProtoFile.cs
@@ -237,7 +237,7 @@
         while (input.ReadTag(out tag, out field_name)) {

           switch (tag) {

             case 0: {

-              throw InvalidProtocolBufferException.InvalidTag();

+              throw pb::InvalidProtocolBufferException.InvalidTag();

             }

             default: {

               if (pb::WireFormat.IsEndGroupTag(tag)) {