Did Google spy on Chrome users with secret audio listeners?

Google has been accused of spying on users with audio listeners, as claimed by Rick Falkvinge, the founder of the Pirate Party.
According to Falkvinge, Google has been “stealth downloading” listening software onto every computer that runs Chrome.
What’s more, he suggests the software automatically “transmits audio data back to Google.”
Here’s the in-brief:
This “black box” of code, which is impossible for users and developers to audit, was downloading, and allegedly executing, a feature that activates the “OK Google” search function.
However, the feature is claimed to have been ‘listening’ in order to hear the phrase prior to activating the search function.
Google claims that this software wasn’t actually activated by default, and that the bug has been fixed as of the latest version of Chromium, which no longer downloads the code as standard.
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But is Google actually spying on us? It’s hard to say, as there’s no real way of knowing what’s inside the “black box” of code.
At the very least, it’s not a great move for Google to include unreadable code in an open-source project.
Open-source communities have a level of trust with software providers, with one of the main appeals of open-source software being that you can see all aspects of the code.
Unfortunately, in this instance, Chromium was downloading, and purportedly executing, code that was impossible to view, which is a breach of trust.
“Chromium, the open-source version of Google Chrome, had abused its position as trusted upstream to insert lines of source code that bypassed [the] audit-then-built process, and which downloaded and installed a black box of unverifiable executable code directly onto computers, essentially rendering them compromised, explained Falkvinge.
He continued: “
Is this another tinfoil hat classic, or is Google really checking up on our private conversations? Let us know your thoughts in the comments.