Support web, limit position to duration.

pubspec.lock

@@ -67,6 +67,11 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  flutter_web_plugins:
+    dependency: "direct main"
+    description: flutter
+    source: sdk
+    version: "0.0.0"
   image:
     dependency: transitive
     description:
@@ -102,13 +107,6 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.5.1"
-  pedantic:
-    dependency: transitive
-    description:
-      name: pedantic
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.8.0+1"
   petitparser:
     dependency: transitive
     description:
@@ -183,7 +181,7 @@ packages:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.11"
+    version: "0.2.14"
   typed_data:
     dependency: transitive
     description: