Fully support `<input type=color>` (#36992)

This change adds a shadow-tree widget for `<input type=color>` elements.
It also involves some changes to the way layout interacts with the DOM,
because currently all `input` and `textarea` elements are rendered as
plain text and their descendants are ignored. This obviously doesn't
work for `<input type={color, date, range, etc}>`.


![image](https://github.com/user-attachments/assets/4f16c3b0-1f79-4095-b19d-1153f5853dd5)

<details><summary>HTML used for the screenshot above</summary>

```html
<input type=color>
```

</details>



Testing: I doubt that this affects WPT tests, because the appearance and
behaviour of the widget is almost entirely unspecified.

---------

Signed-off-by: Simon Wülker <simon.wuelker@arcor.de>

1 files changed, 23 insertions, 2 deletions

diff --git a/components/script/dom/node.rs b/components/script/dom/node.rs
index 5f08abce354..17235543906 100644
--- a/components/script/dom/node.rs
+++ b/components/script/dom/node.rs
@@ -50,7 +50,6 @@ use style::stylesheets::{Stylesheet, UrlExtraData};
 use uuid::Uuid;
 use xml5ever::serialize as xml_serialize;
 
-use super::globalscope::GlobalScope;
 use crate::conversions::Convert;
 use crate::document_loader::DocumentLoader;
 use crate::dom::attr::Attr;
@@ -92,13 +91,14 @@ use crate::dom::documenttype::DocumentType;
 use crate::dom::element::{CustomElementCreationMode, Element, ElementCreator, SelectorWrapper};
 use crate::dom::event::{Event, EventBubbles, EventCancelable};
 use crate::dom::eventtarget::EventTarget;
+use crate::dom::globalscope::GlobalScope;
 use crate::dom::htmlbodyelement::HTMLBodyElement;
 use crate::dom::htmlcanvaselement::{HTMLCanvasElement, LayoutHTMLCanvasElementHelpers};
 use crate::dom::htmlcollection::HTMLCollection;
 use crate::dom::htmlelement::HTMLElement;
 use crate::dom::htmliframeelement::{HTMLIFrameElement, HTMLIFrameElementLayoutMethods};
 use crate::dom::htmlimageelement::{HTMLImageElement, LayoutHTMLImageElementHelpers};
-use crate::dom::htmlinputelement::{HTMLInputElement, LayoutHTMLInputElementHelpers};
+use crate::dom::htmlinputelement::{HTMLInputElement, InputType, LayoutHTMLInputElementHelpers};
 use crate::dom::htmllinkelement::HTMLLinkElement;
 use crate::dom::htmlslotelement::{HTMLSlotElement, Slottable};
 use crate::dom::htmlstyleelement::HTMLStyleElement;
@@ -1612,6 +1612,8 @@ pub(crate) trait LayoutNodeHelpers<'dom> {
     /// attempting to read or modify the opaque layout data of this node.
     unsafe fn clear_style_and_layout_data(self);
 
+    /// Whether this element is a `<input>` rendered as text or a `<textarea>`.
+    fn is_text_input(&self) -> bool;
     fn text_content(self) -> Cow<'dom, str>;
     fn selection(self) -> Option<Range<usize>>;
     fn image_url(self) -> Option<ServoUrl>;
@@ -1776,6 +1778,25 @@ impl<'dom> LayoutNodeHelpers<'dom> for LayoutDom<'dom, Node> {
         self.unsafe_get().layout_data.borrow_mut_for_layout().take();
     }
 
+    fn is_text_input(&self) -> bool {
+        let type_id = self.type_id_for_layout();
+        if type_id ==
+            NodeTypeId::Element(ElementTypeId::HTMLElement(
+                HTMLElementTypeId::HTMLInputElement,
+            ))
+        {
+            let input = self.unsafe_get().downcast::<HTMLInputElement>().unwrap();
+
+            // FIXME: All the non-color input types currently render as text
+            input.input_type() != InputType::Color
+        } else {
+            type_id ==
+                NodeTypeId::Element(ElementTypeId::HTMLElement(
+                    HTMLElementTypeId::HTMLTextAreaElement,
+                ))
+        }
+    }
+
     fn text_content(self) -> Cow<'dom, str> {
         if let Some(text) = self.downcast::<Text>() {
             return text.upcast().data_for_layout().into();