[google_maps_flutter_web] Render custom Marker icons.

[ditman]

Description

This PR adds support for fromBytes BitmapDescriptors, so Markers can have programmatically-generated icons in web.

This also fixes an issue where custom Marker icons were not being rendered as part of the "initial geometry" (there was a TODO/question about it). Now they should work as expected.

(Tangentially, this also enables defaultMarkerWithHue, which can be implemented by computing the bytes of the rotated hue of a default Marker image, similar to the code on this jsfiddle).

Related Issues

• Fixes [google_maps_flutter_web] Custom BitmapDescriptor for icon in Marker does not appear on web flutter#66622
• Fixes [google_maps_flutter_web] Markers are not generated from bytes flutter#67048

Checklist

Before you create this PR confirm that it meets all requirements listed below by checking the relevant checkboxes ([x]). This will ensure a smooth and quick review process.

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• My PR includes unit or integration tests for all changed/updated/fixed behaviors (See Contributor Guide).
• All existing and new tests are passing.
• I updated/added relevant documentation (doc comments with ///).
• The analyzer (flutter analyze) does not report any problems on my PR.
• I read and followed the Flutter Style Guide.
• The title of the PR starts with the name of the plugin surrounded by square brackets, e.g. [shared_preferences]
• I updated pubspec.yaml with an appropriate new version according to the pub versioning philosophy.
• I updated CHANGELOG.md to add a description of the change.
• I signed the CLA.
• I am willing to follow-up on review comments in a timely manner.

Breaking Change

Does your PR require plugin users to manually update their apps to accommodate your change?

• No, this is not a breaking change.

[cyanglaz]

LGTM

[ditman]

This has been published. Please try: google_maps_flutter_web: ^0.1.0+8