Tear out or duplicate what's unique for WindowServer from Widgets.

This turned into a huge refactoring that somehow also includes
making locks recursive/reentrant.

WindowServer/WSFrameBuffer.cpp

@@ -0,0 +1,46 @@
+#include "WSFrameBuffer.h"
+#include <Widgets/GraphicsBitmap.h>
+#include <AK/Assertions.h>
+
+WSFrameBuffer* s_the;
+
+void WSFrameBuffer::initialize()
+{
+    s_the = nullptr;
+}
+
+WSFrameBuffer& WSFrameBuffer::the()
+{
+    ASSERT(s_the);
+    return *s_the;
+}
+
+WSFrameBuffer::WSFrameBuffer(unsigned width, unsigned height)
+    : WSScreen(width, height)
+{
+    ASSERT(!s_the);
+    s_the = this;
+}
+
+WSFrameBuffer::WSFrameBuffer(RGBA32* data, unsigned width, unsigned height)
+    : WSScreen(width, height)
+    , m_data(data)
+{
+    ASSERT(!s_the);
+    s_the = this;
+}
+
+
+WSFrameBuffer::~WSFrameBuffer()
+{
+}
+
+void WSFrameBuffer::show()
+{
+}
+
+RGBA32* WSFrameBuffer::scanline(int y)
+{
+    unsigned pitch = sizeof(RGBA32) * width();
+    return reinterpret_cast<RGBA32*>(((byte*)m_data) + (y * pitch));
+}