LibGUI: Add Widget focus policies

Every widget now has a GUI::FocusPolicy that determines how it can
receive focus:

- NoFocus: The widget is not focusable (default)
- TabFocus: The widget can be focused using the tab key.
- ClickFocus: The widget can be focused by clicking on it.
- StrongFocus: Both of the above.

For widgets that have a focus proxy, getting/setting the focus policy
will affect the proxy instead.

Applications/Browser/ConsoleWidget.cpp

@@ -109,6 +109,8 @@ ConsoleWidget::ConsoleWidget()
         print_html(JS::MarkupGenerator::html_from_value(m_interpreter->vm().last_value()));
     };
 
+    set_focus_proxy(m_input);
+
     auto& clear_button = bottom_container.add<GUI::Button>();
     clear_button.set_size_policy(GUI::SizePolicy::Fixed, GUI::SizePolicy::Fixed);
     clear_button.set_preferred_size(22, 22);
@@ -165,8 +167,4 @@ void ConsoleWidget::clear_output()
     m_output_view->update();
 }
 
-void ConsoleWidget::focusin_event(GUI::FocusEvent&)
-{
-    m_input->set_focus(true);
-}
 }

Applications/Browser/ConsoleWidget.h

@@ -47,9 +47,6 @@ public:
 private:
     ConsoleWidget();
 
-    virtual bool accepts_focus() const override { return true; }
-    virtual void focusin_event(GUI::FocusEvent&) override;
-
     RefPtr<GUI::TextBox> m_input;
     RefPtr<Web::InProcessWebView> m_output_view;
     RefPtr<Web::DOM::Element> m_output_container;

Applications/FontEditor/GlyphMapWidget.cpp

@@ -34,6 +34,7 @@ GlyphMapWidget::GlyphMapWidget(Gfx::Font& mutable_font)
 {
     m_glyph_count = mutable_font.glyph_count();
     set_relative_rect({ 0, 0, preferred_width(), preferred_height() });
+    set_focus_policy(GUI::FocusPolicy::StrongFocus);
 }
 
 GlyphMapWidget::~GlyphMapWidget()

Applications/FontEditor/GlyphMapWidget.h

@@ -53,7 +53,6 @@ public:
 
 private:
     explicit GlyphMapWidget(Gfx::Font&);
-    virtual bool accepts_focus() const override { return true; }
     virtual void paint_event(GUI::PaintEvent&) override;
     virtual void mousedown_event(GUI::MouseEvent&) override;
     virtual void keydown_event(GUI::KeyEvent&) override;

Applications/HexEditor/HexEditor.cpp

@@ -42,6 +42,7 @@
 
 HexEditor::HexEditor()
 {
+    set_focus_policy(GUI::FocusPolicy::StrongFocus);
     set_scrollbars_enabled(true);
     set_font(Gfx::Font::default_fixed_width_font());
     set_background_role(ColorRole::Base);

Applications/HexEditor/HexEditor.h

@@ -74,7 +74,6 @@ protected:
     virtual void mouseup_event(GUI::MouseEvent&) override;
     virtual void mousemove_event(GUI::MouseEvent&) override;
     virtual void keydown_event(GUI::KeyEvent&) override;
-    virtual bool accepts_focus() const override { return true; }
 
 private:
     bool m_readonly { false };

Applications/Piano/SamplerWidget.cpp

@@ -105,7 +105,7 @@ SamplerWidget::SamplerWidget(TrackManager& track_manager)
     m_open_button = m_open_button_and_recorded_sample_name_container->add<GUI::Button>();
     m_open_button->set_size_policy(GUI::SizePolicy::Fixed, GUI::SizePolicy::Fixed);
     m_open_button->set_preferred_size(24, 24);
-    m_open_button->set_focusable(false);
+    m_open_button->set_focus_policy(GUI::FocusPolicy::TabFocus);
     m_open_button->set_icon(Gfx::Bitmap::load_from_file("/res/icons/16x16/open.png"));
     m_open_button->on_click = [this](auto) {
         Optional<String> open_path = GUI::FilePicker::get_open_filepath(window());

Applications/PixelPaint/ImageEditor.cpp

@@ -36,6 +36,7 @@ namespace PixelPaint {
 
 ImageEditor::ImageEditor()
 {
+    set_focus_policy(GUI::FocusPolicy::StrongFocus);
 }
 
 ImageEditor::~ImageEditor()

Applications/PixelPaint/ImageEditor.h

@@ -82,8 +82,6 @@ public:
 private:
     ImageEditor();
 
-    virtual bool accepts_focus() const override { return true; }
-
     virtual void paint_event(GUI::PaintEvent&) override;
     virtual void second_paint_event(GUI::PaintEvent&) override;
     virtual void mousedown_event(GUI::MouseEvent&) override;