Desktop: Isolate CEF-rendered UI into separate crate and process (#4321)

* Extract CEF rendered UI into a separate process and crate

* Review

* Review

* Review

* Review

* Remove necessary workarounds

* Block on frame copy ack

* Crop and resample frames correctly

* Skip blank frames

* Fix deps

* Fix fmt

* Fix clippy warning

* Review

* Fix todo

desktop/ui/src/internal/context_menu_handler.rs

@@ -0,0 +1,66 @@
+use cef::rc::{Rc, RcImpl};
+use cef::sys::{_cef_context_menu_handler_t, cef_base_ref_counted_t};
+use cef::{ImplContextMenuHandler, WrapContextMenuHandler};
+
+pub(crate) struct ContextMenuHandlerImpl {
+	object: *mut RcImpl<_cef_context_menu_handler_t, Self>,
+}
+impl ContextMenuHandlerImpl {
+	pub(crate) fn new() -> Self {
+		Self { object: std::ptr::null_mut() }
+	}
+}
+
+impl ImplContextMenuHandler for ContextMenuHandlerImpl {
+	fn run_context_menu(
+		&self,
+		_browser: Option<&mut cef::Browser>,
+		_frame: Option<&mut cef::Frame>,
+		_params: Option<&mut cef::ContextMenuParams>,
+		_model: Option<&mut cef::MenuModel>,
+		_callback: Option<&mut cef::RunContextMenuCallback>,
+	) -> std::ffi::c_int {
+		// Prevent context menu
+		1
+	}
+
+	fn run_quick_menu(
+		&self,
+		_browser: Option<&mut cef::Browser>,
+		_frame: Option<&mut cef::Frame>,
+		_location: Option<&cef::Point>,
+		_size: Option<&cef::Size>,
+		_edit_state_flags: cef::QuickMenuEditStateFlags,
+		_callback: Option<&mut cef::RunQuickMenuCallback>,
+	) -> std::ffi::c_int {
+		// Prevent quick menu
+		1
+	}
+
+	fn get_raw(&self) -> *mut _cef_context_menu_handler_t {
+		self.object.cast()
+	}
+}
+
+impl Clone for ContextMenuHandlerImpl {
+	fn clone(&self) -> Self {
+		unsafe {
+			let rc_impl = &mut *self.object;
+			rc_impl.interface.add_ref();
+		}
+		Self { object: self.object }
+	}
+}
+impl Rc for ContextMenuHandlerImpl {
+	fn as_base(&self) -> &cef_base_ref_counted_t {
+		unsafe {
+			let base = &*self.object;
+			std::mem::transmute(&base.cef_object)
+		}
+	}
+}
+impl WrapContextMenuHandler for ContextMenuHandlerImpl {
+	fn wrap_rc(&mut self, object: *mut RcImpl<_cef_context_menu_handler_t, Self>) {
+		self.object = object;
+	}
+}