Provide callback to create mojo AndroidOverlays to AVDA.

content/gpu/gpu_child_thread.h

Index: content/gpu/gpu_child_thread.h
diff --git a/content/gpu/gpu_child_thread.h b/content/gpu/gpu_child_thread.h
index cfc258d89dc09bfa7883980e7e0e2e4463d34a01..d86ce7abc3c0ffe5eb19822480e950ce3125b9f8 100644
--- a/content/gpu/gpu_child_thread.h
+++ b/content/gpu/gpu_child_thread.h
@@ -29,6 +29,7 @@
 #include "gpu/ipc/service/gpu_channel_manager_delegate.h"
 #include "gpu/ipc/service/gpu_config.h"
 #include "gpu/ipc/service/x_util.h"
+#include "media/base/android_overlay_mojo_factory.h"
 #include "mojo/public/cpp/bindings/associated_binding_set.h"
 #include "mojo/public/cpp/bindings/binding_set.h"
 #include "services/service_manager/public/interfaces/service_factory.mojom.h"
@@ -115,6 +116,12 @@ class GpuChildThread : public ChildThreadImpl,
     return gpu_service_->gpu_channel_manager();
   }
 
+#if defined(OS_ANDROID)
+  static std::unique_ptr<media::AndroidOverlay> CreateAndroidOverlay(
+      const base::UnguessableToken& routing_token,
+      media::AndroidOverlayConfig);
+#endif
+
   // Set this flag to true if a fatal error occurred before we receive the
   // OnInitialize message, in which case we just declare ourselves DOA.
   const bool dead_on_arrival_;