Add the Mojo implementation of authenticator.mojom's MakeCredential.

content/public/common/content_features.cc

Index: content/public/common/content_features.cc
diff --git a/content/public/common/content_features.cc b/content/public/common/content_features.cc
index db54f942d9f89023a6776c110375ed3e38babf79..e0dbbef1380499d464c3d453240ed1f55388dc04 100644
--- a/content/public/common/content_features.cc
+++ b/content/public/common/content_features.cc
@@ -303,6 +303,11 @@ const base::Feature kWebAssemblyStreaming{"WebAssemblyStreaming",
 const base::Feature kWebAssemblyTrapHandler{"WebAssemblyTrapHandler",
                                             base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Controls whether the WebAuthentication API is enabled:
+// https://w3c.github.io/webauthn
+const base::Feature kWebAuth{"WebAuthentication",
+                             base::FEATURE_DISABLED_BY_DEFAULT};
+
 // If WebGL Image Chromium is allowed, this feature controls whether it is
 // enabled.
 const base::Feature kWebGLImageChromium{"WebGLImageChromium",