LibWeb: Abstract the image decoding via Web::ImageDecoding::Decoder

After this change, LibWeb now expects Web::ImageDecoding::Decoder to be
pre-initialized with a concrete implementation before using the webpage.
The previous implementation, based on the ImageDecoder service, has been
provided directly through an adapter in LibWebClient, and is now used as
the default value by WebContent.

Userland/Libraries/LibWeb/CMakeLists.txt

@@ -377,7 +377,7 @@ set(GENERATED_SOURCES
 )
 
 serenity_lib(LibWeb web)
-target_link_libraries(LibWeb LibCore LibJS LibMarkdown LibGemini LibGUI LibGfx LibTextCodec LibProtocol LibImageDecoderClient LibWasm LibXML)
+target_link_libraries(LibWeb LibCore LibJS LibMarkdown LibGemini LibGUI LibGfx LibTextCodec LibProtocol LibWasm LibXML)
 link_with_unicode_data(LibWeb)
 
 generate_js_wrappers(LibWeb)

Userland/Libraries/LibWeb/HTML/HTMLLinkElement.cpp

@@ -155,7 +155,7 @@ bool HTMLLinkElement::load_favicon_and_use_if_window_is_active()
         return false;
 
     RefPtr<Gfx::Bitmap> favicon_bitmap;
-    auto decoded_image = Web::image_decoder_client().decode_image(resource()->encoded_data());
+    auto decoded_image = Web::ImageDecoding::Decoder::the().decode_image(resource()->encoded_data());
     if (!decoded_image.has_value() || decoded_image->frames.is_empty()) {
         dbgln("Could not decode favicon {}", resource()->url());
         return false;

Userland/Libraries/LibWeb/ImageDecoding.cpp

@@ -1,23 +1,32 @@
 /*
  * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2022, Dex♪ <dexes.ttp@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #include <LibWeb/ImageDecoding.h>
 
-namespace Web {
+namespace Web::ImageDecoding {
 
-ImageDecoderClient::Client& image_decoder_client()
+static RefPtr<Decoder> s_decoder;
+
+Decoder::Decoder() = default;
+
+Decoder::~Decoder() = default;
+
+void Decoder::initialize(RefPtr<Decoder>&& decoder)
 {
-    static RefPtr<ImageDecoderClient::Client> image_decoder_client;
-    if (!image_decoder_client) {
-        image_decoder_client = ImageDecoderClient::Client::try_create().release_value_but_fixme_should_propagate_errors();
-        image_decoder_client->on_death = [&] {
-            image_decoder_client = nullptr;
-        };
+    s_decoder = move(decoder);
+}
+
+Decoder& Decoder::the()
+{
+    if (!s_decoder) [[unlikely]] {
+        dbgln("Web::ImageDecoding::Decoder was not initialized!");
+        VERIFY_NOT_REACHED();
     }
-    return *image_decoder_client;
+    return *s_decoder;
 }
 
 }

Userland/Libraries/LibWeb/ImageDecoding.h

@@ -1,15 +1,40 @@
 /*
  * Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2022, Dex♪ <dexes.ttp@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #pragma once
 
-#include <LibImageDecoderClient/Client.h>
+#include <AK/RefPtr.h>
+#include <AK/Vector.h>
+#include <LibGfx/Bitmap.h>
 
-namespace Web {
+namespace Web::ImageDecoding {
 
-ImageDecoderClient::Client& image_decoder_client();
+struct Frame {
+    RefPtr<Gfx::Bitmap> bitmap;
+    size_t duration { 0 };
+};
+
+struct DecodedImage {
+    bool is_animated { false };
+    u32 loop_count { 0 };
+    Vector<Frame> frames;
+};
+
+class Decoder : public RefCounted<Decoder> {
+public:
+    virtual ~Decoder();
+
+    static void initialize(RefPtr<Decoder>&&);
+    static Decoder& the();
+
+    virtual Optional<DecodedImage> decode_image(ReadonlyBytes) = 0;
+
+protected:
+    explicit Decoder();
+};
 
 }

Userland/Libraries/LibWeb/Loader/FrameLoader.cpp

@@ -75,8 +75,7 @@ static bool build_text_document(DOM::Document& document, ByteBuffer const& data)
 
 static bool build_image_document(DOM::Document& document, ByteBuffer const& data)
 {
-    NonnullRefPtr decoder = image_decoder_client();
-    auto image = decoder->decode_image(data);
+    auto image = ImageDecoding::Decoder::the().decode_image(data);
     if (!image.has_value() || image->frames.is_empty())
         return false;
     auto const& frame = image->frames[0];
@@ -209,7 +208,7 @@ bool FrameLoader::load(LoadRequest& request, Type type)
                 if (data.is_empty())
                     return;
                 RefPtr<Gfx::Bitmap> favicon_bitmap;
-                auto decoded_image = image_decoder_client().decode_image(data);
+                auto decoded_image = ImageDecoding::Decoder::the().decode_image(data);
                 if (!decoded_image.has_value() || decoded_image->frames.is_empty()) {
                     dbgln("Could not decode favicon {}", favicon_url);
                 } else {

Userland/Libraries/LibWeb/Loader/ImageResource.cpp

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <AK/Function.h>
 #include <LibGfx/Bitmap.h>
 #include <LibWeb/ImageDecoding.h>
 #include <LibWeb/Loader/ImageResource.h>
@@ -46,8 +47,7 @@ void ImageResource::decode_if_needed() const
     if (!m_decoded_frames.is_empty())
         return;
 
-    NonnullRefPtr decoder = image_decoder_client();
-    auto image = decoder->decode_image(encoded_data());
+    auto image = ImageDecoding::Decoder::the().decode_image(encoded_data());
 
     if (image.has_value()) {
         m_loop_count = image.value().loop_count;