autoload/magit/utils.vim: add magit#utils#start_profile function

autoload/magit/utils.vim

@@ -173,3 +173,13 @@ endfunction
 function! magit#utils#bufnr()
 	return s:bufnr
 endfunction
+
+function! magit#utils#start_profile(...)
+	let prof_file = ( a:0 == 1 ) ? a:1 : "/tmp/vimagit.log"
+	execute "profile start " . prof_file . " | profile pause"
+	profile! file */plugin/magit.vim
+	profile! file */autoload/magit/*
+	profile! file */common/magit_common.vim
+	profile! file */syntax/magit.vim
+	profile continue
+endfunction