LibPDF: Use MatrixMatrixConversion when possible

Reduces time spent rendering page 3 of 0000849.pdf from 1.32s to 1.13s
on my machine.

Also reduces the time to run Meta/test_pdf.py on 0000.zip
(without 0000849.pdf) from 56s to 54s.

Userland/Libraries/LibPDF/ColorSpace.cpp

@@ -495,11 +495,12 @@ PDFErrorOr<NonnullRefPtr<ColorSpace>> ICCBasedColorSpace::create(Document* docum
 ICCBasedColorSpace::ICCBasedColorSpace(NonnullRefPtr<Gfx::ICC::Profile> profile)
     : m_profile(profile)
 {
+    m_map = sRGB()->matrix_matrix_conversion(profile);
 }
 
 PDFErrorOr<ColorOrStyle> ICCBasedColorSpace::style(ReadonlySpan<Value> arguments) const
 {
-    Vector<u8> bytes;
+    Vector<float, 4> components;
     for (size_t i = 0; i < arguments.size(); ++i) {
         auto const& arg = arguments[i];
         VERIFY(arg.has_number());
@@ -514,9 +515,16 @@ PDFErrorOr<ColorOrStyle> ICCBasedColorSpace::style(ReadonlySpan<Value> arguments
                 number = (number + 128.0f) / 255.0f;
         }
 
-        bytes.append(static_cast<u8>(number * 255.0f));
+        components.append(number);
     }
 
+    if (m_map.has_value())
+        return m_map->map(FloatVector3 { components[0], components[1], components[2] });
+
+    Vector<u8, 4> bytes;
+    for (auto component : components)
+        bytes.append(static_cast<u8>(component * 255.0f));
+
     auto pcs = TRY(m_profile->to_pcs(bytes));
     Array<u8, 3> output;
     TRY(sRGB()->from_pcs(m_profile, pcs, output.span()));

Userland/Libraries/LibPDF/ColorSpace.h

@@ -195,6 +195,7 @@ private:
 
     static RefPtr<Gfx::ICC::Profile> s_srgb_profile;
     NonnullRefPtr<Gfx::ICC::Profile> m_profile;
+    Optional<Gfx::ICC::MatrixMatrixConversion> m_map;
 };
 
 class LabColorSpace final : public ColorSpace {