Support .flutter-plugins-dependencies

[jmagman]

Description

Parse .flutter-plugins-dependencies instead of the old .flutter-plugins to only embed the ios-enabled plugins via CocoaPods.

.flutter-plugins was a flat list of all plugins and their pub cache path, regardless of supported platform:

device_info=/Users/m/.pub-cache/hosted/pub.dartlang.org/device_info-0.4.2+4/

.flutter-plugins-dependencies is json:

{
   "info":"This is a generated file; do not edit or check into version control.",
   "plugins":{
      "ios":[
         {
            "name":"device_info",
            "path":"/Users/m/.pub-cache/hosted/pub.dartlang.org/device_info-0.4.2+4/",
            "dependencies":[
            ]
         }
      ],
      "android":[
         {
            "name":"device_info",
            "path":"/Users/m/.pub-cache/hosted/pub.dartlang.org/device_info-0.4.2+4/",
            "dependencies":[
            ]
         }
      ],
      "macos":[
      ],
      "linux":[
      ],
      "windows":[
      ],
      "web":[
      ]
   },
   "dependencyGraph":[
      {
         "name":"device_info",
         "dependencies":[
         ]
      }
   ],
   "date_created":"2020-06-09 13:50:39.352998",
   "version":"1.19.0-6.0.pre.38"
}

See https://docs.google.com/document/d/1W_IpXetVIgjHipKnu-zPHnDApdiwXR0RfugY6Sm8NAg/edit

Related Issues

Fixes #39659

Tests

Updated integration test to test a plugin that doesn't support iOS.

Checklist

• I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• I signed the [CLA].
• I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement].
• I read the [Tree Hygiene] wiki page, which explains my responsibilities.
• I updated/added relevant documentation (doc comments with ///).
• All existing and new tests are passing.
• The analyzer (flutter analyze --flutter-repo) does not report any problems on my PR.
• I am willing to follow-up on review comments in a timely manner.

Breaking Change

• No, no existing tests failed, so this is not a breaking change.
• Yes, this is a breaking change. If not, delete the remainder of this section.

[fluttergithubbot]

It looks like this pull request may not have tests. Please make sure to add tests before merging. If you need an exemption to this rule, contact Hixie on the #hackers channel in Chat.

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing.

[jmagman]

Ruby std lib module available since Ruby 0.4, CocoaPods depends on it, safe to use here.

[stuartmorgan-g]

LGTM!

[christopherfujino]

LGTM, with a nit about linking in comment to flutter.dev/go/plugins-list-migration