I can\'t believe that neither a Google or SO search has turned up a definitive answer or even much discussion for this, but:
Is it possible to edit/customize keyboar
My solution is using Autohotkey, a tool that I use for shortcuts in any app.
I make and run an .ahk script like this:
#IfWinActive ahk_class Chrome_WidgetWin_1 ; Chrome browser
F2::Send, ^b ; toggle breakpoint (Ctrl+b)
^b::Send, ^m ; use Ctrl+b for something else
It's simple: only when Chrome browser window is active, override F2 key and simulate Ctrl+b, which is official Chrome shortcut to toggle breakpoint.
I actually run my ahk script when Windows starts, so shortcuts are always active.
You can add more shortcuts. You can use different browser or app. One thing that I can't improve yet is listening for shortcuts only when web developer tools in browser are active, maybe there's a way.