Renderer: Implement new render scheduling (#10936)

Implements a new render scheduling method, where we triple buffer when necessary.

Enabled by default, improves FPS on underpowered devices.

---------

Co-authored-by: Mihai Fufezan <mihai@fufexan.net>

src/helpers/MonitorFrameScheduler.hpp

@@ -0,0 +1,35 @@
+#pragma once
+
+#include "Monitor.hpp"
+
+#include <chrono>
+
+class CEGLSync;
+
+class CMonitorFrameScheduler {
+  public:
+    using hrc = std::chrono::high_resolution_clock;
+
+    CMonitorFrameScheduler(PHLMONITOR m);
+
+    CMonitorFrameScheduler(const CMonitorFrameScheduler&)            = delete;
+    CMonitorFrameScheduler(CMonitorFrameScheduler&&)                 = delete;
+    CMonitorFrameScheduler& operator=(const CMonitorFrameScheduler&) = delete;
+    CMonitorFrameScheduler& operator=(CMonitorFrameScheduler&&)      = delete;
+
+    void                    onSyncFired();
+    void                    onPresented();
+    void                    onFrame();
+
+  private:
+    bool            canRender();
+    void            onFinishRender();
+
+    bool            m_renderAtFrame = true;
+    bool            m_pendingThird  = false;
+    hrc::time_point m_lastRenderBegun;
+
+    PHLMONITORREF   m_monitor;
+
+    UP<CEGLSync>    m_sync;
+};