Chrome: We've featured extensions before to find and mute tabs when you can't find the source. The newest Chrome beta removes the need by adding a clearly visible icon whenever a tab is playing audio.
In addition to finding audio, Chrome Beta 32 will also show you a different icon whenever a tab is using your webcam. Other changes include automatic blocking of malware downloads, which should be handy for those who end up on riskier corners of the internet.
Track down those noisy tabs [Google Chrome Blog]