Revert "Auto merge of #2473 - wincent:no-lazy, r=Valloric"

This reverts commit c182c0529b1bc7faa7158ad88fcd5a2b1cf439d9, reversing
changes made to 48b7ccef76c9f15b8fc0227b5e661eb55e483459.

README.md

@@ -2882,19 +2882,6 @@ executable first in your PATH when the virtual environment is active then if
 you set `g:ycm_python_binary_path` to just `'python'` it will be found as the
 first Python and used to run [JediHTTP][].
 
-### I want to defer loading of YouCompleteMe until after Vim finishes booting
-
-In recent versions of Vim, you can install YCM in a folder under
-`~/.vim/pack/*/opt` and then load it once the user is idle via an autocommand:
-
-```viml
-augroup load_ycm
-  autocmd!
-  autocmd CursorHold, CursorHoldI * :packadd YouCompleteMe
-                                \ | autocmd! load_ycm
-augroup END
-```
-
 Contributor Code of Conduct
 ---------------------------
 

plugin/youcompleteme.vim

@@ -128,7 +128,16 @@ let g:ycm_goto_buffer_command =
 let g:ycm_disable_for_files_larger_than_kb =
       \ get( g:, 'ycm_disable_for_files_larger_than_kb', 1000 )
 
-call youcompleteme#Enable()
+" On-demand loading. Let's use the autoload folder and not slow down vim's
+" startup procedure.
+if has( 'vim_starting' ) " loading at startup
+  augroup youcompletemeStart
+    autocmd!
+    autocmd VimEnter * call youcompleteme#Enable()
+  augroup END
+else " manual loading with :packadd
+  call youcompleteme#Enable()
+endif
 
 " This is basic vim plugin boilerplate
 call s:restore_cpo()