Implement location.reload(), location.assign() and location setter

I'm not sure that _any_ location instance should be able to change the page URL.
But you can't create a new location (i.e. new Location() isn't valid), and the
only two ways I know of are via `window.location` and `document.location` both
of which _should_ alter the location of the window/document.

Author: karlseguin

src/browser/html/document.zig

@@ -174,6 +174,10 @@ pub const HTMLDocument = struct {
         return try parser.documentHTMLGetLocation(Location, self);
     }
 
+    pub fn set_location(_: *const parser.DocumentHTML, url: []const u8, page: *Page) !void {
+        return page.navigateFromWebAPI(url);
+    }
+
     pub fn get_designMode(_: *parser.DocumentHTML) []const u8 {
         return "off";
     }

src/browser/html/location.zig

@@ -69,18 +69,17 @@ pub const Location = struct {
         return "";
     }
 
-    // TODO
-    pub fn _assign(_: *Location, url: []const u8) !void {
-        _ = url;
+    pub fn _assign(_: *const Location, url: []const u8, page: *Page) !void {
+        return page.navigateFromWebAPI(url);
     }
 
-    // TODO
-    pub fn _replace(_: *Location, url: []const u8) !void {
-        _ = url;
+    pub fn _replace(_: *const Location, url: []const u8, page: *Page) !void {
+        return page.navigateFromWebAPI(url);
     }
 
-    // TODO
-    pub fn _reload(_: *Location) !void {}
+    pub fn _reload(_: *const Location, page: *Page) !void {
+        return page.navigateFromWebAPI(page.url.raw);
+    }
 
     pub fn _toString(self: *Location, page: *Page) ![]const u8 {
         return try self.get_href(page);

src/browser/html/window.zig

@@ -100,6 +100,10 @@ pub const Window = struct {
         return &self.location;
     }
 
+    pub fn set_location(_: *const Window, url: []const u8, page: *Page) !void {
+        return page.navigateFromWebAPI(url);
+    }
+
     pub fn get_console(self: *Window) *Console {
         return &self.console;
     }

src/browser/page.zig

@@ -541,23 +541,25 @@ pub const Page = struct {
             .a => {
                 const element: *parser.Element = @ptrCast(node);
                 const href = (try parser.elementGetAttribute(element, "href")) orelse return;
-
-                // We cannot navigate immediately as navigating will delete the DOM tree, which holds this event's node.
-                // As such we schedule the function to be called as soon as possible.
-                // NOTE Using the page.arena assumes that the scheduling loop does use this object after invoking the callback
-                // If that changes we may want to consider storing DelayedNavigation in the session instead.
-                const arena = self.arena;
-                const navi = try arena.create(DelayedNavigation);
-                navi.* = .{
-                    .session = self.session,
-                    .href = try arena.dupe(u8, href),
-                };
-                _ = try self.loop.timeout(0, &navi.navigate_node);
+                try self.navigateFromWebAPI(href);
             },
             else => {},
         }
     }
 
+    // As such we schedule the function to be called as soon as possible.
+    // The page.arena is safe to use here, but the transfer_arena exists
+    // specifically for this type of lifetime.
+    pub fn navigateFromWebAPI(self: *Page, url: []const u8) !void {
+        const arena = self.session.transfer_arena;
+        const navi = try arena.create(DelayedNavigation);
+        navi.* = .{
+            .session = self.session,
+            .url = try arena.dupe(u8, url),
+        };
+        _ = try self.loop.timeout(0, &navi.navigate_node);
+    }
+
     pub fn getOrCreateNodeWrapper(self: *Page, comptime T: type, node: *parser.Node) !*T {
         if (try self.getNodeWrapper(T, node)) |wrap| {
             return wrap;
@@ -579,16 +581,15 @@ pub const Page = struct {
 };
 
 const DelayedNavigation = struct {
-    navigate_node: Loop.CallbackNode = .{ .func = DelayedNavigation.delay_navigate },
+    url: []const u8,
     session: *Session,
-    href: []const u8,
+    navigate_node: Loop.CallbackNode = .{ .func = delayNavigate },
 
-    fn delay_navigate(node: *Loop.CallbackNode, repeat_delay: *?u63) void {
+    fn delayNavigate(node: *Loop.CallbackNode, repeat_delay: *?u63) void {
         _ = repeat_delay;
         const self: *DelayedNavigation = @fieldParentPtr("navigate_node", node);
-        self.session.pageNavigate(self.href) catch |err| {
-            // TODO: should we trigger a specific event here?
-            log.err(.page, "delayed navigation error", .{ .err = err });
+        self.session.pageNavigate(self.url) catch |err| {
+            log.err(.page, "delayed navigation error", .{ .err = err, .url = self.url });
         };
     }
 };