I don't know if Google's browser installs it, but at least at some time in the past Google was giving out software components via download to enable video chat through Gmail. It was a mess, including a separate background application, a Safari plug-in and
two Quicktime components. Obviously you've still got at least one of the Quicktime components installed.
Look for these files on your system:
/Library/Application Support/Google/GoogleTalkPlugin.app
/Library/QuickTime/Google Camera Adapter 0.component
/Library/QuickTime/Google Camera Adapter 1.component
/Library/Receipts/GoogleVoiceandVideo.pkg
/Library/Internet Plug-Ins/googletalkbrowserplugin.plugin
~/Library/Application Support/Google/GoogleTalkPlugin.app
~/Library/QuickTime/Google Camera Adapter 0.component
~/Library/QuickTime/Google Camera Adapter 1.component
~/Library/Receipts/GoogleVoiceandVideo.pkg
~/Library/Internet Plug-Ins/googletalkbrowserplugin.plugin
If you want to get rid of this junk, you can try removing them all, then rebooting. I can't promise that'll work, though, because I'm not positive this list is complete.
Take off, and nuke the site from orbit. It's the only way to be sure.