Update constructor APIs TooltipTheme, ToggleButtonsTheme, PopupMenuTheme

[HansMuller]

The constructor signatures for TooltipTheme, ToggleButtonsTheme, PopupMenuTheme have been incompatibly changed. They require just one theme data parameter.

For example the TooltipTheme constructor was defined like this:

const PopupMenuTheme({
  Key key,
  Color color,
  ShapeBorder shape,
  double elevation,
  TextStyle textStyle,
  Widget child,
}) : data = PopupMenuThemeData(
       color: color,
       shape: shape,
       elevation: elevation,
       textStyle: textStyle,
     ),
     super(key: key, child: child);
}) : assert(data != null), super(key: key, child: child);

final PopupMenuThemeData data;

It's now defined like this:

const PopupMenuTheme({
  Key key,
  @required this.data,
  Widget child,
}) : assert(data != null), super(key: key, child: child);

final PopupMenuThemeData data;

Not having a theme data parameter makes it difficult to override an inherited theme’s configuration. For example to override the inherited PopupMenuTheme one would have to write:

PopupMenuThemeData inheritedTheme = PopupMenuTheme.of(context);
PopupMenuTheme(
  color: Colors.green, // the only property to be changed
  shape: inheritedTheme.shape,
  elevation: inheritedTheme.elevation,
  textStyle: inheritedTheme.textStyle,
  child: myWidgetSubtree,
)

This is tedious, error prone, and likely to rot when TooltipThemeData is extended. It's also inconsistent with Theme and ThemeData. Better to just have a TooltipThemeData valued data constructor parameter, since copyWith can be applied to ToolTipThemeData.

TooltipTheme(
  data: TooltipTheme.of(context).copyWith(
    height: myNewTooltipHeight, // the only property to be changed
  ),
  child: myWidgetSubtree,
)

These APIs were added just last week: PopupMenuTheme #36088 TooltipTheme #36030 ToggleButtonsTheme #34599

Code that had already adopted the new APIs can easily be updated as shown in the example above.

[shihaohong]

LGTM