MouseTracker 移至渲染

MouseTracker and related symbols are moved from the gestures package, resulting in error messages such as undefined classes or methods. Import them from rendering package instead.

Prior to this change MouseTracker was part of the gestures package. This brought troubles when we found out that code related to MouseTracker often wanted to import from the rendering package.

Since MouseTracker turned out to be more connected to rendering than gestures, we have moved it and its related code to rendering.

The file mouse_tracking.dart has been moved from the gestures package to rendering. All symbols in the said file have been moved without keeping backward compatibility.

If you see error of "Undefined class" or "Undefined name" of the following symbols:

• MouseDetectorAnnotationFinder
• MouseTracker
• MouseTrackerAnnotation
• PointerEnterEventListener
• PointerExitEventListener
• PointerHoverEventListener

You should add the following import:

import 'package:flutter/rendering.dart';

Landed in version: 1.16.3
In stable release: 1.17

API documentation:

• MouseDetectorAnnotationFinder
• MouseTracker
• MouseTrackerAnnotation
• PointerEnterEventListener
• PointerExitEventListener
• PointerHoverEventListener

Relevant issues:

• Transform mouse events to the local coordinate system
• Move annotations to a separate tree

Relevant PR:

• Move mouse_tracking.dart to rendering