This one is slightly offtopic. I often see people misinterpret the vocabulary "chrom*something" as something related to Google webbroser or Chromium webbroser. But there is another truth, the word
chrome basically meant an application UI and some code to display interactive elements. So if you have software from mozilla (be it iceweasel, icedove, firefox, thunderbird) you likely have something with chrome on your system (i.e. Windows-firefoy a file chrome.manifest)
User interface chrome , the borders and widgets that frame the content part of a window
Summary
Chrome is originally a term for the parts of a web browser's user interface other than the web page it is showing.
"Chrome" is also often used to refer to the Google Chrome web browser.
In depth
Originally "Chrome" referred to the browser's user interface: that is, any toolbars, menu bars, tabs, and so on, that surround the web page being displayed.
By extension, chrome code or chrome-privileged code is the name given to the JavaScript code in Firefox that implements the browser itself, as opposed to the JavaScript code downloaded with a web page, that's referred to as content code. Chrome code runs with system privileges. If chrome code is compromised, the attacker can take over the user's computer. By contrast, content code is untrusted and runs with a greatly reduced privilege level. Code added by extensions is chrome-privileged.
So you can even enter chrome://-URLs in your Iceweasel addressbar, for example
The "About" page --> chrome://browser/content/aboutDialog.xul
Skin Infos --> chrome://global/skin/global.css
Certificate viewer --> chrome://pippki/content/certViewer.xul
And many, many more:
http://kb.mozillazine.org/Dev_:_Firefox_Chrome_URLs