exo: Update cursor on wl_pointer::set_cursor

The cursor scale and rotation must be updated on pointer enter, even
though neither the surface nor the hotspot changed.

BUG=730843
TEST=caroline: Cursor is not stale on pointer enter.

Review-Url: https://codereview.chromium.org/2935753002
Cr-Commit-Position: refs/heads/master@{#478660}

components/exo/pointer.cc

@@ -133,8 +133,11 @@ void Pointer::SetCursor(Surface* surface, const gfx::Point& hotspot) {
     cursor_changed = true;
 
   // Early out if cursor did not change.
-  if (!cursor_changed)
+  if (!cursor_changed) {
+    // Cursor scale or rotation may have changed.
+    UpdateCursor();
     return;
+  }
 
   // If |surface_| is set then asynchronously capture a snapshot of cursor,
   // otherwise cancel pending capture and immediately set the cursor to "none".