Update web/ samples to work with Flutter SDK (#134)

* add package:http dependency in dad_jokes

* add package:http dependency in filipino_cuisine

* don't build package:http demos until flutter/flutter#34858 is resolved

* update gallery

* update github_dataviz

* update particle_background

* don't build github_dataviz (uses package:http)

* update slide_puzzle

* update spinning_square

* update timeflow

* update vision_challenge

* update charts

* update dad_jokes

* update filipino cuisine

* ignore build output

* update timeflow and vision_challenge

* update slide_puzzle

* don't commit build/ directory

* move preview.png images to assets

* fix path url join

* update readme

* update web/readme.md

web/gallery/pubspec.lock

@@ -2,256 +2,169 @@
 # See https://dart.dev/tools/pub/glossary#lockfile
 packages:
   analyzer:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: analyzer
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.37.0"
+    version: "0.36.4"
   archive:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: archive
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.10"
   args:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: args
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.5.2"
   async:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.3.0"
-  bazel_worker:
-    dependency: transitive
-    description:
-      name: bazel_worker
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.1.21"
   boolean_selector:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: boolean_selector
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.0.5"
-  build:
-    dependency: transitive
-    description:
-      name: build
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.1.5"
-  build_config:
-    dependency: transitive
-    description:
-      name: build_config
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.4.1"
-  build_daemon:
-    dependency: transitive
-    description:
-      name: build_daemon
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.0.0"
-  build_modules:
-    dependency: transitive
-    description:
-      name: build_modules
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.4.1"
-  build_resolvers:
-    dependency: transitive
-    description:
-      name: build_resolvers
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.0.6"
-  build_runner:
-    dependency: "direct dev"
-    description:
-      name: build_runner
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.6.5"
-  build_runner_core:
-    dependency: transitive
-    description:
-      name: build_runner_core
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "3.0.7"
-  build_web_compilers:
-    dependency: "direct dev"
-    description:
-      name: build_web_compilers
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.1.4"
-  built_collection:
-    dependency: transitive
-    description:
-      name: built_collection
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "4.2.2"
-  built_value:
-    dependency: transitive
-    description:
-      name: built_value
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "6.7.0"
   charcode:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: charcode
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.1.2"
-  checked_yaml:
-    dependency: transitive
-    description:
-      name: checked_yaml
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.0.1"
-  code_builder:
-    dependency: transitive
-    description:
-      name: code_builder
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "3.2.0"
   collection:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: collection
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.14.11"
+  connectivity:
+    dependency: "direct main"
+    description:
+      name: connectivity
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.4.3+7"
   convert:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: convert
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.1"
   crypto:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: crypto
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.6"
+    version: "2.1.2"
   csslib:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: csslib
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.16.1"
-  dart_style:
-    dependency: transitive
-    description:
-      name: dart_style
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.2.9"
-  fixnum:
-    dependency: transitive
-    description:
-      name: fixnum
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.10.9"
-  flutter_web:
+  cupertino_icons:
     dependency: "direct main"
     description:
-      path: "packages/flutter_web"
-      ref: HEAD
-      resolved-ref: "88a6325290b75326c072ae63bf3016e15a08fccc"
-      url: "https://github.com/flutter/flutter_web"
-    source: git
-    version: "0.0.0"
-  flutter_web_test:
+      name: cupertino_icons
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.1.2"
+  device_info:
+    dependency: "direct main"
+    description:
+      name: device_info
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.4.0+2"
+  file:
     dependency: "direct dev"
     description:
-      path: "packages/flutter_web_test"
-      ref: HEAD
-      resolved-ref: "88a6325290b75326c072ae63bf3016e15a08fccc"
-      url: "https://github.com/flutter/flutter_web"
-    source: git
+      name: file
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "5.0.8+1"
+  flutter:
+    dependency: "direct main"
+    description: flutter
+    source: sdk
     version: "0.0.0"
-  flutter_web_ui:
+  flutter_gallery_assets:
     dependency: "direct main"
     description:
-      path: "packages/flutter_web_ui"
-      ref: HEAD
-      resolved-ref: "88a6325290b75326c072ae63bf3016e15a08fccc"
-      url: "https://github.com/flutter/flutter_web"
-    source: git
+      name: flutter_gallery_assets
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.1.9+2"
+  flutter_test:
+    dependency: "direct dev"
+    description: flutter
+    source: sdk
     version: "0.0.0"
   front_end:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: front_end
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.1.20"
+    version: "0.1.19"
   glob:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: glob
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.1.7"
-  graphs:
-    dependency: transitive
-    description:
-      name: graphs
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.2.0"
   html:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: html
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.14.0+2"
   http:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: http
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.12.0+2"
   http_multi_server:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: http_multi_server
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.0"
   http_parser:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: http_parser
       url: "https://pub.dartlang.org"
     source: hosted
     version: "3.1.3"
+  image:
+    dependency: "direct dev"
+    description:
+      name: image
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.1.4"
   intl:
     dependency: "direct main"
     description:
@@ -260,224 +173,229 @@ packages:
     source: hosted
     version: "0.15.8"
   io:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: io
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.3.3"
   js:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: js
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.6.1+1"
-  json_annotation:
-    dependency: transitive
+  json_rpc_2:
+    dependency: "direct dev"
     description:
-      name: json_annotation
+      name: json_rpc_2
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.4.0"
+    version: "2.1.0"
   kernel:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: kernel
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.3.20"
-  logging:
-    dependency: transitive
-    description:
-      name: logging
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.11.3+2"
+    version: "0.3.19"
   matcher:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.12.5"
   meta:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.1.7"
   mime:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: mime
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.9.6+3"
   multi_server_socket:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: multi_server_socket
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.0.2"
   node_preamble:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: node_preamble
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.4.6"
   package_config:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: package_config
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.5"
+    version: "1.1.0"
   package_resolver:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: package_resolver
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.0.10"
   path:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: path
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.6.4"
   pedantic:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: pedantic
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.8.0+1"
+  petitparser:
+    dependency: "direct dev"
+    description:
+      name: petitparser
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.4.0"
+  platform:
+    dependency: "direct dev"
+    description:
+      name: platform
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.2.1"
   pool:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: pool
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.4.0"
-  protobuf:
-    dependency: transitive
+  process:
+    dependency: "direct dev"
     description:
-      name: protobuf
+      name: process
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.13.15"
+    version: "3.0.11"
   pub_semver:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: pub_semver
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.4.2"
-  pubspec_parse:
-    dependency: transitive
-    description:
-      name: pubspec_parse
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.1.4"
   quiver:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: quiver
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.4"
-  scratch_space:
-    dependency: transitive
+    version: "2.0.5"
+  scoped_model:
+    dependency: "direct main"
     description:
-      name: scratch_space
+      name: scoped_model
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.0.4"
+    version: "1.0.1"
   shelf:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: shelf
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.7.5"
   shelf_packages_handler:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: shelf_packages_handler
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.0.4"
   shelf_static:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: shelf_static
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.2.8"
   shelf_web_socket:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: shelf_web_socket
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.2.3"
-  source_map_stack_trace:
+  shrine_images:
+    dependency: "direct main"
+    description:
+      name: shrine_images
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.1.2"
+  sky_engine:
     dependency: transitive
+    description: flutter
+    source: sdk
+    version: "0.0.99"
+  source_map_stack_trace:
+    dependency: "direct dev"
     description:
       name: source_map_stack_trace
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.1.5"
   source_maps:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: source_maps
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.10.8"
   source_span:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.5.5"
   stack_trace:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: stack_trace
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.9.3"
   stream_channel:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: stream_channel
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.0"
-  stream_transform:
-    dependency: transitive
-    description:
-      name: stream_transform
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.0.19"
   string_scanner:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: string_scanner
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.0.5"
   term_glyph:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: term_glyph
       url: "https://pub.dartlang.org"
@@ -489,69 +407,84 @@ packages:
       name: test
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.6.5"
+    version: "1.6.3"
   test_api:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.6"
+    version: "0.2.5"
   test_core:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: test_core
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.7"
-  timing:
-    dependency: transitive
-    description:
-      name: timing
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.1.1+1"
+    version: "0.2.5"
   typed_data:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: typed_data
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.1.6"
+  url_launcher:
+    dependency: "direct main"
+    description:
+      name: url_launcher
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "5.1.2"
   vector_math:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.8"
-  vm_service_lib:
-    dependency: transitive
+  video_player:
+    dependency: "direct main"
     description:
-      name: vm_service_lib
+      name: video_player
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "3.22.2+1"
+    version: "0.10.1+6"
+  vm_service_client:
+    dependency: "direct dev"
+    description:
+      name: vm_service_client
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.2.6+2"
   watcher:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: watcher
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.9.7+12"
   web_socket_channel:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: web_socket_channel
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.14"
+    version: "1.0.15"
+  xml:
+    dependency: "direct dev"
+    description:
+      name: xml
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.5.0"
   yaml:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: yaml
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.16"
 sdks:
-  dart: ">=2.3.0 <3.0.0"
+  dart: ">=2.4.0 <3.0.0"
+  flutter: ">=1.5.0 <2.0.0"