Fix issue with importing packages where the package name included a dot

lib/protobuf_field.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of protoc;
 
 class ProtobufField {
   static final RegExp HEX_LITERAL_REGEX =
       new RegExp(r'^0x[0-9a-f]+$', multiLine: false, caseSensitive: false);
   static final RegExp INTEGER_LITERAL_REGEX = new RegExp(r'^[+-]?[0-9]+$');
@@ skipping 249 matching lines @@
             initialization = '()${SP}=>${SP}<int>[$byteList]';
           }
         }
         break;
       case FieldDescriptorProto_Type.TYPE_GROUP:
         ProtobufContainer groupType = context[field.typeName];
         if (groupType != null) {
           typePackage = groupType.package;
           baseType = groupType.classname;
           typeString = write(groupType.classname);
-          prefixedBaseType = groupType.package + '.' + baseType;
+          prefixedBaseType = groupType.packageImportPrefix + '.' + baseType;
           prefixedTypeString = write(prefixedBaseType);
           codedStreamType = 'Group';
         } else {
           throw 'FAILURE: Unknown group type reference ${field.typeName}';
         }
         initialization = '()${SP}=>${SP}new ${baseType}()';
         prefixedInitialization = '()${SP}=>${SP}new ${prefixedBaseType}()';
         break;
       case FieldDescriptorProto_Type.TYPE_MESSAGE:
         ProtobufContainer messageType = context[field.typeName];
         if (messageType != null) {
           typePackage = messageType.package;
           baseType = messageType.classname;
           typeString = write(baseType);
-          prefixedBaseType = messageType.package + '.' + baseType;
+          prefixedBaseType = messageType.packageImportPrefix + '.' + baseType;
           prefixedTypeString = write(prefixedBaseType);
           codedStreamType = 'Message';
         } else {
           throw 'FAILURE: Unknown message type reference ${field.typeName}';
         }
         initialization = '()${SP}=>${SP}new ${baseType}()';
         prefixedInitialization = '()${SP}=>${SP}new ${prefixedBaseType}()';
         break;
       case FieldDescriptorProto_Type.TYPE_ENUM:
         EnumGenerator enumType = context[field.typeName];
         if (enumType != null) {
           typePackage = enumType.package;
           baseType = enumType.classname;
           typeString = write(enumType.classname);
           codedStreamType = 'Enum';
-          prefixedBaseType = enumType.package + '.' + baseType;
+          prefixedBaseType = enumType.packageImportPrefix + '.' + baseType;
           prefixedTypeString = write(prefixedBaseType);
           packable = true;
           if (!repeats) {
             if (field.hasDefaultValue() && !field.defaultValue.isEmpty) {
               initialization =
                   '()${SP}=>${SP}${baseType}.${field.defaultValue}';
               prefixedInitialization =
                   '()${SP}=>${SP}${prefixedBaseType}.${field.defaultValue}';
             } else if (!enumType._canonicalValues.isEmpty) {
               initialization =
@@ skipping 73 matching lines @@
         return 2; // Length-delimited
       case FieldDescriptorProto_Type.TYPE_GROUP:
         return 3; // Start group
       case FieldDescriptorProto_Type.TYPE_FLOAT:
       case FieldDescriptorProto_Type.TYPE_FIXED32:
       case FieldDescriptorProto_Type.TYPE_SFIXED32:
         return 5; // 32-bit
     }
   }
 }