WebContent: Fix const-correctness issues

Userland/Services/WebContent/ConnectionFromClient.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2022, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2020-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
  * Copyright (c) 2021-2023, Linus Groh <linusg@serenityos.org>
  * Copyright (c) 2022, Tobias Christiansen <tobyase@serenityos.org>
@@ -117,7 +117,7 @@ void ConnectionFromClient::set_viewport_rect(Gfx::IntRect const& rect)
 
 void ConnectionFromClient::add_backing_store(i32 backing_store_id, Gfx::ShareableBitmap const& bitmap)
 {
-    m_backing_stores.set(backing_store_id, *bitmap.bitmap());
+    m_backing_stores.set(backing_store_id, *const_cast<Gfx::ShareableBitmap&>(bitmap).bitmap());
 }
 
 void ConnectionFromClient::remove_backing_store(i32 backing_store_id)

Userland/Services/WebContent/PageHost.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2020-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021-2022, Linus Groh <linusg@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -60,7 +60,7 @@ Gfx::Palette PageHost::palette() const
     return Gfx::Palette(*m_palette_impl);
 }
 
-void PageHost::set_palette_impl(Gfx::PaletteImpl const& impl)
+void PageHost::set_palette_impl(Gfx::PaletteImpl& impl)
 {
     m_palette_impl = impl;
     if (auto* document = page().top_level_browsing_context().active_document())

Userland/Services/WebContent/PageHost.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2020-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021-2023, Linus Groh <linusg@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
@@ -29,7 +29,7 @@ public:
 
     virtual void paint(Web::DevicePixelRect const& content_rect, Gfx::Bitmap&) override;
 
-    void set_palette_impl(Gfx::PaletteImpl const&);
+    void set_palette_impl(Gfx::PaletteImpl&);
     void set_viewport_rect(Web::DevicePixelRect const&);
     void set_screen_rects(Vector<Gfx::IntRect, 4> const& rects, size_t main_screen_index) { m_screen_rect = rects[main_screen_index].to_type<Web::DevicePixels>(); }
     void set_device_pixels_per_css_pixel(float device_pixels_per_css_pixel) { m_device_pixels_per_css_pixel = device_pixels_per_css_pixel; }