chromeos: decode video into NV12 format instead of RGBA in vaapi decoder

ui/ozone/platform/headless/headless_surface_factory.cc

Index: ui/ozone/platform/headless/headless_surface_factory.cc
diff --git a/ui/ozone/platform/headless/headless_surface_factory.cc b/ui/ozone/platform/headless/headless_surface_factory.cc
index 56f06819038778745498c3e9855e7d1660628f81..215335292b8142aad4384c5cc93875e88eb4b827 100644
--- a/ui/ozone/platform/headless/headless_surface_factory.cc
+++ b/ui/ozone/platform/headless/headless_surface_factory.cc
@@ -81,6 +81,9 @@ class TestPixmap : public gfx::NativePixmap {
   int GetDmaBufOffset(size_t plane) const override { return 0; }
   uint64_t GetDmaBufModifier(size_t plane) const override { return 0; }
   gfx::BufferFormat GetBufferFormat() const override { return format_; }
+  gfx::BufferUsage GetBufferUsage() const override {
+    return gfx::BufferUsage::SCANOUT;
+  }
   gfx::Size GetBufferSize() const override { return gfx::Size(); }
   bool ScheduleOverlayPlane(gfx::AcceleratedWidget widget,
                             int plane_z_order,