cmd/internal/browser: add chromium to the list of browsers

Many linux distros distribute Chromium instead of Chrome.

Change-Id: I5474d94da28a7c79bdd7181f77472d4ce73bb225
Reviewed-on: https://go-review.googlesource.com/29293Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/internal/browser/browser.go

@@ -25,7 +25,12 @@ func Commands() [][]string {
 	default:
 		cmds = append(cmds, []string{"xdg-open"})
 	}
-	cmds = append(cmds, []string{"chrome"}, []string{"google-chrome"}, []string{"firefox"})
+	cmds = append(cmds,
+		[]string{"chrome"},
+		[]string{"google-chrome"},
+		[]string{"chromium"},
+		[]string{"firefox"},
+	)
 	return cmds
 }