Update pkg:markdown to v2
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5f7a819..3771d56 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.19.1
+* Update `package:markdown` to `2.0.0`, which includes many improvements –
+  especially to the parsing of links.
+
 ## 0.19.0
 * Build documentation through the Package object (#1659)
 * New flag, --link-to-remote, which will cause Dartdoc to link symbols to their originating
diff --git a/lib/dartdoc.dart b/lib/dartdoc.dart
index fac8d60..66bb355 100644
--- a/lib/dartdoc.dart
+++ b/lib/dartdoc.dart
@@ -37,7 +37,7 @@
 
 const String name = 'dartdoc';
 // Update when pubspec version changes.
-const String dartdocVersion = '0.19.0';
+const String dartdocVersion = '0.19.1-dev';
 
 /// Generates Dart documentation for all public Dart libraries in the given
 /// directory.
diff --git a/lib/src/markdown_processor.dart b/lib/src/markdown_processor.dart
index 983a9e2..13c6c25 100644
--- a/lib/src/markdown_processor.dart
+++ b/lib/src/markdown_processor.dart
@@ -814,7 +814,7 @@
       {Iterable<md.BlockSyntax> blockSyntaxes,
       Iterable<md.InlineSyntax> inlineSyntaxes,
       md.ExtensionSet extensionSet,
-      linkResolver,
+      md.Resolver linkResolver,
       imageLinkResolver})
       : super(
             blockSyntaxes: blockSyntaxes,
@@ -971,7 +971,10 @@
   /// Returns a tuple of longHtml, shortHtml, hasExtendedDocs
   /// (longHtml is NULL if !processFullDocs)
   Tuple3<String, String, bool> _renderMarkdownToHtml(bool processFullDocs) {
-    md.Node _linkResolver(String name) {
+    md.Node _linkResolver(String name, [String _]) {
+      if (name.isEmpty) {
+        return null;
+      }
       return new md.Text(_linkDocReference(name, _element, commentRefs));
     }
 
diff --git a/pubspec.lock b/pubspec.lock
index 3bc99dd..00dac62 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -168,7 +168,7 @@
       name: markdown
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.1"
+    version: "2.0.0"
   matcher:
     dependency: transitive
     description:
@@ -401,4 +401,4 @@
     source: hosted
     version: "2.1.13"
 sdks:
-  dart: ">=2.0.0-dev.23.0 <=2.0.0-dev.53.0"
+  dart: ">=2.0.0-dev.23.0 <=2.0.0-dev.54.0"
diff --git a/pubspec.yaml b/pubspec.yaml
index bd598e2..b22c359 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: dartdoc
 # Also update the `version` field in lib/dartdoc.dart.
-version: 0.19.0
+version: 0.19.1-dev
 author: Dart Team <misc@dartlang.org>
 description: A documentation generator for Dart.
 homepage: https://github.com/dart-lang/dartdoc
@@ -18,7 +18,7 @@
   # least version 3.0.3 to work around an issue with 3.0.2.
   http_parser: '>=3.0.3 <4.0.0'
   logging: ^0.11.3+1
-  markdown: ^1.0.0
+  markdown: ^2.0.0
   mustache4dart: ^2.1.1
   package_config: '>=0.1.5 <2.0.0'
   path: ^1.3.0
diff --git a/testing/test_package_docs/index.html b/testing/test_package_docs/index.html
index 7ffc362..21500f6 100644
--- a/testing/test_package_docs/index.html
+++ b/testing/test_package_docs/index.html
@@ -4,7 +4,7 @@
   <meta charset="utf-8">
   <meta http-equiv="X-UA-Compatible" content="IE=edge">
   <meta name="viewport" content="width=device-width, initial-scale=1">
-  <meta name="generator" content="made with love by dartdoc 0.19.0">
+  <meta name="generator" content="made with love by dartdoc 0.19.1-dev">
   <meta name="description" content="test_package API docs, for the Dart programming language.">
   <title>test_package - Dart API docs</title>