X11: Fix cursor:move on older DMZ/Adwaita cursor themes

After CL [1], the cursor name changed from "all-scroll" to "move" on
X11.  On older DMZ/Adwaita cursor themes (default on Ubuntu 16.04 LTS),
this resulted in the DND-move cursor (left-arrow with a small move
icon) instead of the all-scroll cursor (four arrows).  The comment
in cursors_aura.cc explains why we should be using all-scroll [2]:

      // Returning "move" is the correct thing here, but Blink doesn't
      // make a distinction between move and all-scroll.  Other
      // platforms use a cursor more consistent with all-scroll, so
      // use that.

This CL restores the cursor CSS name to all-scroll to fix older
cursor themes.  The newer themes don't have this issue.

[1] https://chromium.googlesource.com/chromium/src/+/4b135039432a487e84547308fea5703a198a1297%5E%21/#F0
[2] https://source.chromium.org/chromium/chromium/src/+/master:ui/base/cursor/cursors_aura.cc;drc=163115502d4bff646602baa9af3b0a8522809351;l=361?originalUrl=https:%2F%2Fcs.chromium.org%2F

BUG=1069738
R=sky

Change-Id: Ib82900c62a23b3efc5ce556b652019ce31045b0e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2145919
Auto-Submit: Thomas Anderson <thomasanderson@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758513}

ui/base/cursor/cursor_loader_x11.cc

@@ -69,7 +69,7 @@ template <typename... Ts>
     case mojom::CursorType::kPointer:
       return LoadFontCursor("left_ptr", XC_left_ptr);
     case mojom::CursorType::kMove:
-      return LoadFontCursor("move", XC_fleur);
+      return LoadFontCursor("all-scroll", XC_fleur);
     case mojom::CursorType::kCross:
       return LoadFontCursor("crosshair", XC_cross);
     case mojom::CursorType::kHand: