Browser+LibWeb: Make sure the default favicon is loaded

Previously in Browser, when we navigate back from a page that has an
icon to a page that does not have an icon, the icon does not update and
the old icon is displayed because FrameLoader does not set the default
favicon when the favicon cannot be loaded. This patch ensures that
Browser receives a new icon bitmap every time a load takes place.

Userland/Applications/Browser/BrowserWindow.cpp

@@ -515,10 +515,6 @@ void BrowserWindow::create_new_tab(URL url, bool activate)
 
     m_tab_widget->set_bar_visible(!is_fullscreen() && m_tab_widget->children().size() > 1);
 
-    auto default_favicon = Gfx::Bitmap::try_load_from_file("/res/icons/16x16/filetype-html.png");
-    VERIFY(default_favicon);
-    m_tab_widget->set_tab_icon(new_tab, default_favicon);
-
     new_tab.on_title_change = [this, &new_tab](auto& title) {
         m_tab_widget->set_tab_title(new_tab, title);
         if (m_tab_widget->active_widget() == &new_tab)

Userland/Libraries/LibWeb/Loader/FrameLoader.cpp

@@ -22,9 +22,15 @@
 
 namespace Web {
 
+static RefPtr<Gfx::Bitmap> s_default_favicon_bitmap;
+
 FrameLoader::FrameLoader(BrowsingContext& browsing_context)
     : m_browsing_context(browsing_context)
 {
+    if (!s_default_favicon_bitmap) {
+        s_default_favicon_bitmap = Gfx::Bitmap::try_load_from_file("/res/icons/16x16/filetype-html.png");
+        VERIFY(s_default_favicon_bitmap);
+    }
 }
 
 FrameLoader::~FrameLoader()
@@ -166,21 +172,24 @@ bool FrameLoader::load(const LoadRequest& request, Type type)
             favicon_url,
             [this, favicon_url](auto data, auto&, auto) {
                 dbgln("Favicon downloaded, {} bytes from {}", data.size(), favicon_url);
+                RefPtr<Gfx::Bitmap> favicon_bitmap;
                 auto decoder = Gfx::ImageDecoder::try_create(data);
                 if (!decoder) {
                     dbgln("No image decoder plugin for favicon {}", favicon_url);
-                    return;
+                } else {
+                    favicon_bitmap = decoder->frame(0).image;
+                    if (!favicon_bitmap)
+                        dbgln("Could not decode favicon {}", favicon_url);
+                    else
+                        dbgln("Decoded favicon, {}", favicon_bitmap->size());
                 }
-                auto frame = decoder->frame(0);
-                auto bitmap = frame.image;
-                if (!bitmap) {
-                    dbgln("Could not decode favicon {}", favicon_url);
-                    return;
-                }
-                dbgln("Decoded favicon, {}", bitmap->size());
-                if (auto* page = browsing_context().page())
-                    page->client().page_did_change_favicon(*bitmap);
+                load_favicon(favicon_bitmap);
+            },
+            [this](auto&, auto) {
+                load_favicon();
             });
+    } else {
+        load_favicon();
     }
 
     return true;
@@ -232,6 +241,16 @@ void FrameLoader::load_error_page(const URL& failed_url, const String& error)
         });
 }
 
+void FrameLoader::load_favicon(RefPtr<Gfx::Bitmap> bitmap)
+{
+    if (auto* page = browsing_context().page()) {
+        if (bitmap)
+            page->client().page_did_change_favicon(*bitmap);
+        else
+            page->client().page_did_change_favicon(*s_default_favicon_bitmap);
+    }
+}
+
 void FrameLoader::resource_did_load()
 {
     auto url = resource()->url();

Userland/Libraries/LibWeb/Loader/FrameLoader.h

@@ -40,6 +40,7 @@ private:
     virtual void resource_did_fail() override;
 
     void load_error_page(const URL& failed_url, const String& error_message);
+    void load_favicon(RefPtr<Gfx::Bitmap> bitmap = nullptr);
     bool parse_document(DOM::Document&, const ByteBuffer& data);
 
     BrowsingContext& m_browsing_context;