patch 8.1.2013: more functions can be used as methods

Problem:    More functions can be used as methods.
Solution:   Make various functions usable as a method.
diff --git a/src/testdir/test_window_cmd.vim b/src/testdir/test_window_cmd.vim
index f2a9f17..9bdae2c 100644
--- a/src/testdir/test_window_cmd.vim
+++ b/src/testdir/test_window_cmd.vim
@@ -72,7 +72,7 @@
 func Test_window_quit()
   e Xa
   split Xb
-  call assert_equal(2, winnr('$'))
+  call assert_equal(2, '$'->winnr())
   call assert_equal('Xb', bufname(winbufnr(1)))
   call assert_equal('Xa', bufname(winbufnr(2)))
 
@@ -88,7 +88,7 @@
   3wincmd s
   call assert_equal(2, winnr('$'))
   call assert_equal(3, winheight(0))
-  call assert_equal(winwidth(1), winwidth(2))
+  call assert_equal(winwidth(1), 2->winwidth())
 
   call assert_fails('botright topleft wincmd s', 'E442:')
   bw
@@ -300,7 +300,7 @@
 
   wincmd +
   call assert_equal(wh1, winheight(1))
-  call assert_equal(wh2, winheight(2))
+  call assert_equal(wh2, 2->winheight())
 
   2wincmd _
   call assert_equal(2, winheight(1))
@@ -845,4 +845,16 @@
   only | tabonly
 endfunc
 
+func Test_winrestview()
+  split runtest.vim
+  normal 50%
+  let view = winsaveview()
+  close
+  split runtest.vim
+  eval view->winrestview()
+  call assert_equal(view, winsaveview())
+
+  bwipe!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab