So when playing with chrome portable, I noticed that it used my current user directory for downloads. While this may be ok for some, this was not a reasonable option for me. I use portable apps from the hard disk of a virtual machine for work. What I like about portable apps is how it is a complete package, without the need for installation (aside from maybe copying a folder). So, for all of you who want to make chrome portable have a relative download directory (relative to the installation path), here it is.
In [App Location]\GoogleChromePortable\Data\profile\Default locate the file named Preferences. Open said file in a text editor (I use Npp portable ) and search for the preference called "download" (quotes included). Change the "default_directory" value to use a double-dot relative directory path. You must change the setting in the Preferences file, as the application does not allow you to select relative paths. Here is the relative path and how it associates to an absolute path.
If the app is located on the root of C:\ then we would have C:\GoogleChromePortable as the root path.
.\\Downloads --> C:\GoogleChromePortable\App\Chrome-bin\18.0.1025.162\Downloads (the 18.0.1025.162 is just hte version number of chrome, it may be different on your machine.
..\\Downloads --> C:\GoogleChromePortable\App\Chrome-bin\Downloads
..\\..\\Downloads --> C:\GoogleChromePortable\App\Downloads
..\\..\\..\\Downloads --> C:\GoogleChromePortable\Downloads
I have portable apps folder structure look like
Apps contains the GoogleChromePortable, along with all other portable apps' folders. So, my downloads path looks like this: ..\\..\\..\\..\\..\\Downloads which points to C:\Portables\Downloads.
I hope someone else also finds this useful!