LibDraw: Introduce (formerly known as SharedGraphics.)

Instead of LibGUI and WindowServer building their own copies of the drawing
and graphics code, let's it in a separate LibDraw library.

This avoids building the code twice, and will encourage better separation
of concerns. :^)

Libraries/LibDraw/Size.h

@@ -0,0 +1,65 @@
+#pragma once
+
+#include <AK/AKString.h>
+#include <AK/LogStream.h>
+
+struct WSAPI_Size;
+
+class Size {
+public:
+    Size() {}
+    Size(int w, int h)
+        : m_width(w)
+        , m_height(h)
+    {
+    }
+    Size(const WSAPI_Size&);
+
+    bool is_null() const { return !m_width && !m_height; }
+    bool is_empty() const { return m_width <= 0 || m_height <= 0; }
+
+    int width() const { return m_width; }
+    int height() const { return m_height; }
+
+    int area() const { return width() * height(); }
+
+    void set_width(int w) { m_width = w; }
+    void set_height(int h) { m_height = h; }
+
+    bool operator==(const Size& other) const
+    {
+        return m_width == other.m_width && m_height == other.m_height;
+    }
+
+    bool operator!=(const Size& other) const
+    {
+        return !(*this == other);
+    }
+
+    Size& operator-=(const Size& other)
+    {
+        m_width -= other.m_width;
+        m_height -= other.m_height;
+        return *this;
+    }
+
+    Size& operator+=(const Size& other)
+    {
+        m_width += other.m_width;
+        m_height += other.m_height;
+        return *this;
+    }
+
+    operator WSAPI_Size() const;
+
+    String to_string() const { return String::format("[%dx%d]", m_width, m_height); }
+
+private:
+    int m_width { 0 };
+    int m_height { 0 };
+};
+
+inline const LogStream& operator<<(const LogStream& stream, const Size& value)
+{
+    return stream << value.to_string();
+}