Make the touch emulator's cursor appear consistently

Web content refreshes its desired cursor on every mouse event, but
TouchEmulator did not, so the custom "grey circle" touch cursor could
get lost when, say, you move your mouse out of and back into its bounds.

This change make the touch emulator work like web content and refresh
its cursor on every mouse event.

Bug: 989006
Change-Id: If9a943b276b250363541384878cea9a2ddab117e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1867090Reviewed-by: Navid Zolghadr <nzolghadr@chromium.org>
Commit-Queue: Sidney San Martín <sdy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#707837}

content/browser/renderer_host/input/touch_emulator.cc

@@ -182,6 +182,8 @@ bool TouchEmulator::HandleMouseEvent(const WebMouseEvent& mouse_event,
   if (!enabled() || mode_ != Mode::kEmulatingTouchFromMouse)
     return false;
 
+  UpdateCursor();
+
   if (mouse_event.button == WebMouseEvent::Button::kRight &&
       mouse_event.GetType() == WebInputEvent::kMouseDown) {
     client_->ShowContextMenuAtPoint(