Fix initialization in MusBrowserCompositorOutputSurface

content/browser/compositor/mus_browser_compositor_output_surface.cc

Index: content/browser/compositor/mus_browser_compositor_output_surface.cc
diff --git a/content/browser/compositor/mus_browser_compositor_output_surface.cc b/content/browser/compositor/mus_browser_compositor_output_surface.cc
index ce3b426a44f88136c9d9d836638e37fd771ac7ae..a274eb9b7e8a3e1b2df76498563c143afd2fc591 100644
--- a/content/browser/compositor/mus_browser_compositor_output_surface.cc
+++ b/content/browser/compositor/mus_browser_compositor_output_surface.cc
@@ -32,7 +32,8 @@ MusBrowserCompositorOutputSurface::MusBrowserCompositorOutputSurface(
     : GpuBrowserCompositorOutputSurface(std::move(context),
                                         update_vsync_parameters_callback,
                                         std::move(overlay_candidate_validator)),
-      ui_window_(window) {
+      ui_window_(window),
+      window_(nullptr) {
   ui_compositor_frame_sink_ = ui_window_->RequestCompositorFrameSink(
       ui::mojom::CompositorFrameSinkType::DEFAULT, context,
       gpu_memory_buffer_manager);
@@ -49,6 +50,7 @@ MusBrowserCompositorOutputSurface::MusBrowserCompositorOutputSurface(
     : GpuBrowserCompositorOutputSurface(std::move(context),
                                         update_vsync_parameters_callback,
                                         std::move(overlay_candidate_validator)),
+      ui_window_(nullptr),
       window_(window) {
   aura::WindowPortMus* window_port = aura::WindowPortMus::Get(window_);
   DCHECK(window_port);