WIP #120 Simplest on/off state history chart

lib/entity_widgets/model_widgets.dart

@@ -0,0 +1,42 @@
+part of '../main.dart';
+
+class EntityModel extends InheritedWidget {
+  const EntityModel({
+    Key key,
+    @required this.entity,
+    @required this.handleTap,
+    @required Widget child,
+  }) : super(key: key, child: child);
+
+  final Entity entity;
+  final bool handleTap;
+
+  static EntityModel of(BuildContext context) {
+    return context.inheritFromWidgetOfExactType(EntityModel);
+  }
+
+  @override
+  bool updateShouldNotify(InheritedWidget oldWidget) {
+    return true;
+  }
+}
+
+class HomeAssistantModel extends InheritedWidget {
+
+  const HomeAssistantModel({
+    Key key,
+    @required this.homeAssistant,
+    @required Widget child,
+  }) : super(key: key, child: child);
+
+  final HomeAssistant homeAssistant;
+
+  static HomeAssistantModel of(BuildContext context) {
+    return context.inheritFromWidgetOfExactType(HomeAssistantModel);
+  }
+
+  @override
+  bool updateShouldNotify(InheritedWidget oldWidget) {
+    return true;
+  }
+}