Support subscriptions by replying to ping message

[CrisBarreiro]

Task/Issue URL: https://app.asana.com/1/137249556945/project/1205008441501016/task/1211092095433618?focus=true

Description

C-S-S sends us a ping message so we have a reference to a reply proxy that we store and use to send messages after a user action is initiated on the native side

Steps to test this PR

Pre-requisites

• Install C-S-S 11.15.0
• Load privacy-config from https://duckduckgo.github.io/privacy-configuration/pr-3624/v4/android-config.json
• Set version to 5.300.1 in version.properties
• Add logs to WebViewCompatBreakageContentScopeJsMessageHandler#process and WebViewCompatWebCompatMessagingPlugin#postMessage
• Enable useNewWebCompatApis under feature flag inventory (enabled by default)

Desktop mode

• Load wikipedia.org
• Open menu
• Switch to desktop mode
• Check desktop mode is loaded

Breakage reporting

• Load a page
• Open menu
• Check subscription with name getBreakageReportValues is sent, and message with method breakageReportResult is received

Disable protections

• Load http://privacy-test-pages.site/privacy-protections/gpc/
• Click start test
• Check:
  • top frame header - "1"
  • top frame JS API - true
  • frame JS API - true
• Open menu
• Click Disable Privacy Protection
• Click start test
• Check:
  • top frame header - ...
  • top frame JS API - ...
  • frame JS API - ...

UI changes

n/a

[CrisBarreiro]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• Support subscriptions by replying to ping message #6616 👈 (View in Graphite)
• Support message responses #6602
• Add support to receive messages #6601
• Add support for addDocumentStartJavaScript #6600 : 1 other dependent PR (#6641 )
• develop

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