1611142 - Replace usage of sendSyncMessage for frame data

Status: NEW

(WebExtensions :: General, enhancement, P2)

Description

[Tomislav Jovanovic :zombie]

https://searchfox.org/mozilla-central/rev/e878e5b8/toolkit/components/extensions/ExtensionProcessScript.jsm#83

There are no sync messages with fission. My plan is to store frame data in cpmm.sharedMem, keyed off browserId from Mossop's bug 1580766.

I think we can also use the existence of that same frame data to replace usage of message managers and frame scripts and tab-content-frameloader-created observer notification to control into which documents we want to inject content script/extension apis.

https://searchfox.org/mozilla-central/rev/e878e5b8/toolkit/components/extensions/ExtensionPolicyService.cpp#464
https://searchfox.org/mozilla-central/rev/e878e5b8/browser/base/content/tab-content.js#111