Use image cache to stop leaking images (#29452)

This PR fixes several possible memory leaks due to loading images in
markdown files and the image viewer, using the new image cache APIs

TODO: 
- [x] Ensure this didn't break rendering in any of the affected
components.

Release Notes:

- Fixed several image related memory leaks

crates/repl/src/notebook/cell.rs

@@ -3,7 +3,9 @@ use std::sync::Arc;
 
 use editor::{Editor, EditorMode, MultiBuffer};
 use futures::future::Shared;
-use gpui::{App, Entity, Hsla, Task, TextStyleRefinement, prelude::*};
+use gpui::{
+    App, Entity, Hsla, RetainAllImageCache, Task, TextStyleRefinement, image_cache, prelude::*,
+};
 use language::{Buffer, Language, LanguageRegistry};
 use markdown_preview::{markdown_parser::parse_markdown, markdown_renderer::render_markdown_block};
 use nbformat::v4::{CellId, CellMetadata, CellType};
@@ -148,6 +150,7 @@ impl Cell {
 
                     MarkdownCell {
                         markdown_parsing_task,
+                        image_cache: RetainAllImageCache::new(cx),
                         languages: languages.clone(),
                         id: id.clone(),
                         metadata: metadata.clone(),
@@ -329,6 +332,7 @@ pub trait RunnableCell: RenderableCell {
 pub struct MarkdownCell {
     id: CellId,
     metadata: CellMetadata,
+    image_cache: Entity<RetainAllImageCache>,
     source: String,
     parsed_markdown: Option<markdown_preview::markdown_elements::ParsedMarkdown>,
     markdown_parsing_task: Task<()>,
@@ -403,12 +407,12 @@ impl Render for MarkdownCell {
                     .child(self.gutter(window, cx))
                     .child(
                         v_flex()
+                            .image_cache(self.image_cache.clone())
                             .size_full()
                             .flex_1()
                             .p_3()
                             .font_ui(cx)
                             .text_size(TextSize::Default.rems(cx))
-                            //
                             .children(parsed.children.iter().map(|child| {
                                 div().relative().child(div().relative().child(
                                     render_markdown_block(child, &mut markdown_render_context),

crates/repl/src/outputs/markdown.rs

@@ -1,5 +1,7 @@
 use anyhow::Result;
-use gpui::{App, ClipboardItem, Context, Entity, Task, Window, div, prelude::*};
+use gpui::{
+    App, ClipboardItem, Context, Entity, RetainAllImageCache, Task, Window, div, prelude::*,
+};
 use language::Buffer;
 use markdown_preview::{
     markdown_elements::ParsedMarkdown, markdown_parser::parse_markdown,
@@ -11,6 +13,7 @@ use crate::outputs::OutputContent;
 
 pub struct MarkdownView {
     raw_text: String,
+    image_cache: Entity<RetainAllImageCache>,
     contents: Option<ParsedMarkdown>,
     parsing_markdown_task: Option<Task<Result<()>>>,
 }
@@ -33,6 +36,7 @@ impl MarkdownView {
 
         Self {
             raw_text: text.clone(),
+            image_cache: RetainAllImageCache::new(cx),
             contents: None,
             parsing_markdown_task: Some(task),
         }
@@ -74,6 +78,7 @@ impl Render for MarkdownView {
             markdown_preview::markdown_renderer::RenderContext::new(None, window, cx);
 
         v_flex()
+            .image_cache(self.image_cache.clone())
             .gap_3()
             .py_4()
             .children(parsed.children.iter().map(|child| {