LibWeb: Remove Gfx::ImageDecoder from ImageLoader

We still use a Gfx::ImageDecoder for GIF images, but there's no need
for the ImageLoader object to have its own pointer to it. Just grab
the ImageDecoder from the ImageResource when needed.

Libraries/LibWeb/Loader/ImageLoader.cpp

@@ -76,10 +76,10 @@ void ImageLoader::resource_did_load()
 #endif
 
     if (resource()->should_decode_in_process()) {
-        m_decoder = resource()->ensure_decoder();
+        auto& decoder = resource()->ensure_decoder();
 
-        if (m_decoder->is_animated() && m_decoder->frame_count() > 1) {
-            const auto& first_frame = m_decoder->frame(0);
+        if (decoder.is_animated() && decoder.frame_count() > 1) {
+            const auto& first_frame = decoder.frame(0);
             m_timer->set_interval(first_frame.duration);
             m_timer->on_timeout = [this] { animate(); };
             m_timer->start();
@@ -95,19 +95,18 @@ void ImageLoader::animate()
     if (!m_visible_in_viewport)
         return;
 
-    auto* decoder = image_decoder();
-    ASSERT(decoder);
+    auto& decoder = resource()->ensure_decoder();
 
-    m_current_frame_index = (m_current_frame_index + 1) % decoder->frame_count();
-    const auto& current_frame = decoder->frame(m_current_frame_index);
+    m_current_frame_index = (m_current_frame_index + 1) % decoder.frame_count();
+    const auto& current_frame = decoder.frame(m_current_frame_index);
 
     if (current_frame.duration != m_timer->interval()) {
         m_timer->restart(current_frame.duration);
     }
 
-    if (m_current_frame_index == decoder->frame_count() - 1) {
+    if (m_current_frame_index == decoder.frame_count() - 1) {
         ++m_loops_completed;
-        if (m_loops_completed > 0 && m_loops_completed == decoder->loop_count()) {
+        if (m_loops_completed > 0 && m_loops_completed == decoder.loop_count()) {
             m_timer->stop();
         }
     }
@@ -123,19 +122,12 @@ void ImageLoader::resource_did_fail()
         on_fail();
 }
 
-void ImageLoader::resource_did_replace_decoder()
-{
-    if (resource()->should_decode_in_process()) {
-        m_decoder = resource()->ensure_decoder();
-    }
-}
-
 bool ImageLoader::has_image() const
 {
     if (!resource())
         return false;
     if (resource()->should_decode_in_process())
-        return image_decoder();
+        return const_cast<ImageResource*>(resource())->ensure_decoder().bitmap();
     return true;
 }
 
@@ -144,7 +136,7 @@ unsigned ImageLoader::width() const
     if (!resource())
         return 0;
     if (resource()->should_decode_in_process())
-        return image_decoder() ? image_decoder()->width() : 0;
+        return const_cast<ImageResource*>(resource())->ensure_decoder().width();
     return bitmap() ? bitmap()->width() : 0;
 }
 
@@ -153,7 +145,7 @@ unsigned ImageLoader::height() const
     if (!resource())
         return 0;
     if (resource()->should_decode_in_process())
-        return image_decoder() ? image_decoder()->height() : 0;
+        return const_cast<ImageResource*>(resource())->ensure_decoder().height();
     return bitmap() ? bitmap()->height() : 0;
 }
 
@@ -161,12 +153,7 @@ const Gfx::Bitmap* ImageLoader::bitmap() const
 {
     if (!resource())
         return nullptr;
-    return resource()->bitmap();
-}
-
-const Gfx::ImageDecoder* ImageLoader::image_decoder() const
-{
-    return m_decoder;
+    return resource()->bitmap(m_current_frame_index);
 }
 
 }

Libraries/LibWeb/Loader/ImageLoader.h

@@ -39,7 +39,6 @@ public:
     void load(const URL&);
 
     const Gfx::Bitmap* bitmap() const;
-    const Gfx::ImageDecoder* image_decoder() const;
 
     bool has_image() const;
 
@@ -56,12 +55,10 @@ private:
     // ^ImageResourceClient
     virtual void resource_did_load() override;
     virtual void resource_did_fail() override;
-    virtual void resource_did_replace_decoder() override;
     virtual bool is_visible_in_viewport() const override { return m_visible_in_viewport; }
 
     void animate();
 
-    RefPtr<Gfx::ImageDecoder> m_decoder;
     mutable bool m_visible_in_viewport { false };
 
     size_t m_current_frame_index { 0 };

Libraries/LibWeb/Loader/ImageResource.cpp

@@ -94,9 +94,6 @@ void ImageResource::update_volatility()
         return;
 
     m_decoder = nullptr;
-    for_each_client([&](auto& client) {
-        static_cast<ImageResourceClient&>(client).resource_did_replace_decoder();
-    });
 }
 
 ImageResourceClient::~ImageResourceClient()

Libraries/LibWeb/Loader/ImageResource.h

@@ -54,7 +54,6 @@ public:
     virtual ~ImageResourceClient();
 
     virtual bool is_visible_in_viewport() const { return false; }
-    virtual void resource_did_replace_decoder() {}
 
 protected:
     ImageResource* resource() { return static_cast<ImageResource*>(ResourceClient::resource()); }