Remove pdf-util-window-pixel-width, fallback to window-body-width

`window-body-width` is available for us to use in Emacs 26.3

Relates to: vedang#26

lisp/pdf-util.el

@@ -43,16 +43,6 @@
 ;; * Compatibility with older Emacssen (< 25.1)
 ;; * ================================================================== *
 
-;; In Emacs 24.3 window-width does not have a PIXELWISE argument.
-(defmacro pdf-util-window-pixel-width (&optional window)
-  "Return the width of WINDOW in pixel."
-  (if (< (cdr (subr-arity (symbol-function 'window-body-width))) 2)
-      (let ((window* (make-symbol "window")))
-        `(let ((,window* ,window))
-           (*  (window-body-width ,window*)
-               (frame-char-width (window-frame ,window*)))))
-    `(window-body-width ,window t)))
-
 ;; In Emacs 24.3 image-mode-winprops leads to infinite recursion.
 (unless (or (> emacs-major-version 24)
             (and (= emacs-major-version 24)

lisp/pdf-view.el

@@ -1135,7 +1135,7 @@ If WINDOW is t, redisplay pages in all windows."
   (let* ((pagesize (pdf-cache-pagesize
                     (or page (pdf-view-current-page window))))
          (slice (pdf-view-current-slice window))
-         (width-scale (/ (/ (float (pdf-util-window-pixel-width window))
+         (width-scale (/ (/ (float (window-body-width window t))
                             (or (nth 2 slice) 1.0))
                          (float (car pagesize))))
          (height (- (nth 3 (window-inside-pixel-edges window))