I am developing a chrome extension that pulls large public keys from webpages. I need to know if I will run into any limitations that I can not find on googles website that relate to their message passing API.
When you use
chrome.runtime.sendMessage, the message is serialized, and sent from the sender's process (e.g. the tab containing the content script) to the extension's process (the background page) in one go. The hard limit of the IPC message is 128 MB. If you send anything bigger than that, the sender's process will be terminated.
Although 50 MB is technically acceptable, you should not try to send so much data. Here is a screenshot of Chrome's task manager right after starting up the browser and sending 50MB of data. The picture shows that it took 5 seconds to get the message from the tab to the background page, and that the browser and tab process both use about 300MB and the extension process 663MB (where the initial values were 32, 17 and 22 MB, respectively).
Messages of a few megabytes are not a problem, however.