Android: Force draw for pending readbacks during Display teardown

content/browser/renderer_host/compositor_impl_android.h

Index: content/browser/renderer_host/compositor_impl_android.h
diff --git a/content/browser/renderer_host/compositor_impl_android.h b/content/browser/renderer_host/compositor_impl_android.h
index 110155653b32c44dbdd919739d234651ed5c3fba..6638afd051f6b5bbf7f1a1d209d6571d6d0ee347 100644
--- a/content/browser/renderer_host/compositor_impl_android.h
+++ b/content/browser/renderer_host/compositor_impl_android.h
@@ -133,10 +133,15 @@ class CONTENT_EXPORT CompositorImpl
       scoped_refptr<cc::VulkanContextProvider> vulkan_context_provider,
       scoped_refptr<cc::ContextProvider> context_provider);
 
+  bool HavePendingReadbacks();
+
   // root_layer_ is the persistent internal root layer, while subroot_layer_
   // is the one attached by the compositor client.
   scoped_refptr<cc::Layer> subroot_layer_;
 
+  // Subtree for hidden layers with CopyOutputRequests on them.
+  scoped_refptr<cc::Layer> readback_layer_tree_;
+
   // Destruction order matters here:
   std::unique_ptr<cc::SurfaceIdAllocator> surface_id_allocator_;
   base::ObserverList<VSyncObserver, true> observer_list_;