Reddit Sources:
Here /here/and here
This was specifically made with Titanfall in mind, but will work with any Origin-based game...
This guide was done using Windows 7
- Step 1. Open Steam and click 'ADD A GAME / Add a Non-Steam Game'. Browse for the Titanfall.exe. Its usually under Start / Computer / (C) / Program Files x86 / Origin Games / Titanfall, for most people. (It may be different for you depending how you have everything set up.) Click Open and hit Add Selected Programs.
- Step 2. Now you need the path to the Origin exe. On most computers it in Start / Computer / (C) / Program Files x86 / Origin. Now while holding SHIFT right click the Origin.exe and select Copy As Path.
- Step 3. Open Steam and find the Titanfall Shortcut we made and right click it then select properties. Under 'Target' paste the file path BEHIND the path that was there when you opened properties in the first place. Make sure there's a space in between the paths and quotations(" ") that appear. Example: "C:\Program Files (x86)\Origin Games\Titanfall\Titanfall.exe" "C:\Program Files (x86)\Origin\Origin.exe" and hit close.
- Step 4. Open Origin and on the top left, click Origin and select Application Settings. Under the General tab, Uncheck 'Automatically Launch Origin When I log into Windows'. Now Under the Advanced Tab, Check 'Automatically Exit After closing a game'.
Now you can Launch the game via your Steam Library, have your Friends List show what Origin game you're playing, and have Steam Overlay enabled while in-game. Doing this, however, will disable Origin's in-game overlay, so ...
OPTIONAL, if you still want access to Origin Friends list for game invites, etc.
- Make sure you launch the game at least once normally. While in game go to your Video options and select Run in a Window and make sure your resolution set in game is the same as your monitor. After thats done you can close the game completely again.
- Now Right click Titanfall in your Origin window and click Game Properties then type in the commands -noborder -windowed
EDIT: added information
HOW TO CREATE A DESKTOP / TASKBAR SHORTCUT
Navigate to your Steam.exe file (normally C:\Program Files (x86)\Steam\Steam.exe)
Add -gameidlaunch <rungameid#> to the Target line in your Shortcut Properties
example: "C:\Program Files (x86)\Steam\Steam.exe" -gameidlaunch 9426159974330925056steam://rungameid/<rungameid#>
To find the rungameid# you can right-click on the game in your Steam Library and add "Create Desktop Shortcut" then right-click and view that shortcut Properties. The URL path will show the # you're looking for like steam://rungameid/<rungameid#>
For me, Titanfall's default (non-working) shortcut looked like this:
URL: steam://rungameid/9426159974330925056
Now with the modified (and working) Steam.exe shortcut it looks like this:
Target: "C:\Program Files (x86)\Steam\Steam.exe" -gameidlaunch 9426159974330925056
Once your shortcut is in place and modified, rename it to whatever game you're running and change the icon to match. For Titanfall I use C:\Program Files (x86)\Origin Games\Titanfall\GDFBinary_en_US_64.dll because it has a prettier icon than the default ;D
