Add flutter_web samples (#75)

web/charts/flutter/pubspec.yaml

@@ -0,0 +1,45 @@
+name: charts_flutter
+version: 0.6.0
+description: Material Design charting library for flutter.
+author: Charts Team <charts_flutter@google.com>
+homepage: https://github.com/google/charts
+
+environment:
+  sdk: '>=2.0.0 <3.0.0'
+
+dependencies:
+  # Pointing this to a local path allows for pointing to the latest code
+  # in Github for open source development.
+  #
+  # The pub version of charts_flutter will point to the pub version of charts_common.
+  # The latest pub version is commented out and shown below as an example.
+  # charts_common: 0.6.0
+  charts_common:
+    path: ../common/
+  collection: ^1.14.5
+  flutter_web: any
+  intl: ^0.15.2
+  logging: any
+  meta: ^1.1.1
+
+
+dev_dependencies:
+  mockito:
+  flutter_web_test: any
+  test: ^1.3.0
+
+# flutter_web packages are not published to pub.dartlang.org
+# These overrides tell the package tools to get them from GitHub
+dependency_overrides:
+  flutter_web:
+    git:
+      url: https://github.com/flutter/flutter_web
+      path: packages/flutter_web
+  flutter_web_test:
+    git:
+      url: https://github.com/flutter/flutter_web
+      path: packages/flutter_web_test
+  flutter_web_ui:
+    git:
+      url: https://github.com/flutter/flutter_web
+      path: packages/flutter_web_ui