Move window event handling into separate functions

app/streaming/video/ffmpeg-renderers/drm.cpp

@@ -280,7 +280,7 @@ void DrmRenderer::prepareToRender()
         else {
             // If we get here prior to the start of a session, just pump and flush ourselves.
             SDL_PumpEvents();
-            SDL_FlushEvent(SDL_WINDOWEVENT);
+            SDLC_FlushWindowEvents();
         }
 
         SDL_SetRenderDrawColor(renderer, 0, 0, 0, SDL_ALPHA_OPAQUE);

app/streaming/video/ffmpeg-renderers/eglvid.cpp

@@ -474,7 +474,7 @@ bool EGLRenderer::initialize(PDECODER_PARAMETERS params)
     else {
         // If we get here prior to the start of a session, just pump and flush ourselves.
         SDL_PumpEvents();
-        SDL_FlushEvent(SDL_WINDOWEVENT);
+        SDLC_FlushWindowEvents();
     }
 
     // Now we finally bail if we failed during SDL_CreateRenderer() above.

app/streaming/video/ffmpeg-renderers/mmal.cpp

@@ -78,7 +78,7 @@ void MmalRenderer::prepareToRender()
     else {
         // If we get here prior to the start of a session, just pump and flush ourselves.
         SDL_PumpEvents();
-        SDL_FlushEvent(SDL_WINDOWEVENT);
+        SDLC_FlushWindowEvents();
     }
 
     SDL_SetRenderDrawColor(m_BackgroundRenderer, 0, 0, 0, SDL_ALPHA_OPAQUE);

app/streaming/video/ffmpeg-renderers/sdlvid.cpp

@@ -191,7 +191,7 @@ bool SdlRenderer::initialize(PDECODER_PARAMETERS params)
     else {
         // If we get here prior to the start of a session, just pump and flush ourselves.
         SDL_PumpEvents();
-        SDL_FlushEvent(SDL_WINDOWEVENT);
+        SDLC_FlushWindowEvents();
     }
 
 #ifdef Q_OS_WIN32