disallow creating tooltip's without hover_content, change the example…

… accordingly

examples/tooltip/src/main.rs

@@ -24,8 +24,10 @@ impl Sandbox for Example {
     fn update(&mut self, _message: Message) {}
 
     fn view(&mut self) -> Element<Message> {
-        let tooltip = Tooltip::new(Text::new("hello").size(60))
-            .hover_content(Text::new("hello but smaller").size(30));
+        let tooltip = Tooltip::new(
+            Text::new("hello").size(60),
+            Text::new("hello but smaller").size(30),
+        );
 
         Container::new(tooltip)
             .width(Length::Fill)

native/src/widget/tooltip.rs

@@ -11,7 +11,7 @@ use crate::{
 pub struct Tooltip<'a, Message, Renderer: self::Renderer> {
     state: State,
     content: Element<'a, Message, Renderer>,
-    hover_content: Option<Element<'a, Message, Renderer>>,
+    hover_content: Element<'a, Message, Renderer>,
 }
 
 impl<'a, Message, Renderer> Tooltip<'a, Message, Renderer>
@@ -21,27 +21,16 @@ where
     /// Creates an empty [`Tooltip`].
     ///
     /// [`Tooltip`]: struct.Tooltip.html
-    pub fn new<T>(content: T) -> Self
+    pub fn new<T>(content: T, hover_content: T) -> Self
     where
         T: Into<Element<'a, Message, Renderer>>,
     {
         Tooltip {
             state: Default::default(),
             content: content.into(),
-            hover_content: None,
+            hover_content: hover_content.into(),
         }
     }
-
-    /// Sets the hover_content of the [`Tooltip`].
-    ///
-    /// [`Tooltip`]: struct.Tooltip.html
-    pub fn hover_content<T>(mut self, hover_content: T) -> Self
-    where
-        T: Into<Element<'a, Message, Renderer>>,
-    {
-        self.hover_content = Some(hover_content.into());
-        self
-    }
 }
 
 #[derive(Debug, Default)]
@@ -126,7 +115,7 @@ where
         if layout.bounds().contains(self.state.cursor_position) {
             Some(overlay::Element::new(
                 self.state.cursor_position,
-                Box::new(Overlay::new(self.hover_content.as_ref()?)),
+                Box::new(Overlay::new(&self.hover_content)),
             ))
         } else {
             None