WindowServer+CPUGraph: Make menu applets be "regular" windows

Instead of implementing menu applets as their own thing, they are now
WSWindows of WSWindowType::MenuApplet.

This makes it much easier to work with them on the client side, since
you can just create a GWindow with the right type and you're in the
menubar doing applet stuff :^)

MenuApplets/CPUGraph/main.cpp

@@ -1,87 +1,83 @@
 #include <AK/CircularQueue.h>
 #include <LibCore/CProcessStatisticsReader.h>
-#include <LibCore/CTimer.h>
-#include <LibDraw/GraphicsBitmap.h>
 #include <LibGUI/GApplication.h>
 #include <LibGUI/GPainter.h>
-#include <LibGUI/GWindowServerConnection.h>
+#include <LibGUI/GWidget.h>
+#include <LibGUI/GWindow.h>
 
-NonnullRefPtr<GraphicsBitmap> create_shared_bitmap(const Size& size)
-{
-    ASSERT(GWindowServerConnection::the().server_pid());
-    ASSERT(!size.is_empty());
-    size_t pitch = round_up_to_power_of_two(size.width() * sizeof(RGBA32), 16);
-    size_t size_in_bytes = size.height() * pitch;
-    auto shared_buffer = SharedBuffer::create_with_size(size_in_bytes);
-    ASSERT(shared_buffer);
-    shared_buffer->share_with(GWindowServerConnection::the().server_pid());
-    return GraphicsBitmap::create_with_shared_buffer(GraphicsBitmap::Format::RGBA32, *shared_buffer, size);
-}
+class GraphWidget final : public GWidget {
+    C_OBJECT(GraphWidget)
+public:
+    GraphWidget()
+        : GWidget(nullptr)
+    {
+        start_timer(1000);
+    }
 
-static void get_cpu_usage(unsigned& busy, unsigned& idle)
-{
-    busy = 0;
-    idle = 0;
+    virtual ~GraphWidget() override {}
 
-    auto all_processes = CProcessStatisticsReader::get_all();
+private:
+    virtual void timer_event(CTimerEvent&) override
+    {
+        unsigned busy;
+        unsigned idle;
+        get_cpu_usage(busy, idle);
+        unsigned busy_diff = busy - m_last_busy;
+        unsigned idle_diff = idle - m_last_idle;
+        m_last_busy = busy;
+        m_last_idle = idle;
+        float cpu = (float)busy_diff / (float)(busy_diff + idle_diff);
+        m_cpu_history.enqueue(cpu);
+        update();
+    }
 
-    for (auto& it : all_processes) {
-        for (auto& jt : it.value.threads) {
-            if (it.value.pid == 0)
-                idle += jt.times_scheduled;
-            else
-                busy += jt.times_scheduled;
+    virtual void paint_event(GPaintEvent& event) override
+    {
+        GPainter painter(*this);
+        painter.add_clip_rect(event.rect());
+        painter.fill_rect(event.rect(), Color::Black);
+        int i = m_cpu_history.capacity() - m_cpu_history.size();
+        for (auto cpu_usage : m_cpu_history) {
+            painter.draw_line(
+                { i, rect().bottom() },
+                { i, (int)(height() - (cpu_usage * (float)height())) },
+                Color::from_rgb(0xaa6d4b));
+            ++i;
         }
     }
-}
+
+    static void get_cpu_usage(unsigned& busy, unsigned& idle)
+    {
+        busy = 0;
+        idle = 0;
+
+        auto all_processes = CProcessStatisticsReader::get_all();
+
+        for (auto& it : all_processes) {
+            for (auto& jt : it.value.threads) {
+                if (it.value.pid == 0)
+                    idle += jt.times_scheduled;
+                else
+                    busy += jt.times_scheduled;
+            }
+        }
+    }
+
+    CircularQueue<float, 30> m_cpu_history;
+    unsigned m_last_busy { 0 };
+    unsigned m_last_idle { 0 };
+};
 
 int main(int argc, char** argv)
 {
     GApplication app(argc, argv);
 
-    Size applet_size(30, 16);
-    Rect applet_rect({}, applet_size);
-
-    CircularQueue<float, 30> cpu_history;
-
-    i32 applet_id = GWindowServerConnection::the().send_sync<WindowServer::CreateMenuApplet>(applet_size)->applet_id();
-    auto bitmap = create_shared_bitmap(applet_size);
-
-    GWindowServerConnection::the().send_sync<WindowServer::SetMenuAppletBackingStore>(applet_id, bitmap->shared_buffer_id());
-
-    unsigned last_busy = 0;
-    unsigned last_idle = 0;
-
-    auto repaint = [&] {
-        unsigned busy;
-        unsigned idle;
-        get_cpu_usage(busy, idle);
-        unsigned busy_diff = busy - last_busy;
-        unsigned idle_diff = idle - last_idle;
-        last_busy = busy;
-        last_idle = idle;
-        float cpu = (float)busy_diff / (float)(busy_diff + idle_diff);
-        cpu_history.enqueue(cpu);
-
-        GPainter painter(*bitmap);
-        painter.fill_rect(applet_rect, Color::Black);
-        int i = cpu_history.capacity() - cpu_history.size();
-        for (auto cpu_usage : cpu_history) {
-            painter.draw_line(
-                { applet_rect.x() + i, applet_rect.bottom() },
-                { applet_rect.x() + i, (int)(applet_rect.y() + (applet_rect.height() - (cpu_usage * (float)applet_rect.height()))) },
-                Color::from_rgb(0xaa6d4b));
-            ++i;
-        }
-
-        GWindowServerConnection::the().send_sync<WindowServer::InvalidateMenuAppletRect>(applet_id, applet_rect);
-    };
-
-    repaint();
-
-    auto timer = CTimer::construct(1000, [&] {
-        repaint();
-    });
+    auto window = GWindow::construct();
+    window->set_window_type(GWindowType::MenuApplet);
+    window->resize(30, 16);
 
+    auto widget = GraphWidget::construct();
+    window->set_main_widget(widget);
+    window->show();
     return app.exec();
 }