LibGfx: Prefer largest image with best depth for ICO display

Some favicons contain multiple icons of the same size, but with
increasing depth. Use the largest one to make things look nicer.

Userland/Libraries/LibGfx/ICOLoader.cpp

@@ -39,6 +39,7 @@ static_assert(AssertSize<ICONDIRENTRY, 16>());
 struct ICOImageDescriptor {
     u16 width;
     u16 height;
+    u16 bits_per_pixel;
     size_t offset;
     size_t size;
     RefPtr<Gfx::Bitmap> bitmap;
@@ -77,7 +78,7 @@ static Optional<ICOImageDescriptor> decode_ico_direntry(InputMemoryStream& strea
     if (stream.handle_any_error())
         return {};
 
-    ICOImageDescriptor desc = { entry.width, entry.height, entry.offset, entry.size, nullptr };
+    ICOImageDescriptor desc = { entry.width, entry.height, entry.bits_per_pixel, entry.offset, entry.size, nullptr };
     if (desc.width == 0)
         desc.width = 256;
     if (desc.height == 0)
@@ -91,10 +92,14 @@ static size_t find_largest_image(ICOLoadingContext const& context)
     size_t max_area = 0;
     size_t index = 0;
     size_t largest_index = 0;
+    u16 max_bits_per_pixel = 0;
     for (auto const& desc : context.images) {
-        if (static_cast<size_t>(desc.width) * static_cast<size_t>(desc.height) > max_area) {
-            max_area = desc.width * desc.height;
-            largest_index = index;
+        if (static_cast<size_t>(desc.width) * static_cast<size_t>(desc.height) >= max_area) {
+            if (desc.bits_per_pixel > max_bits_per_pixel) {
+                max_area = desc.width * desc.height;
+                largest_index = index;
+                max_bits_per_pixel = desc.bits_per_pixel;
+            }
         }
         ++index;
     }