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

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index 260c28e23b0541928285fb393f15dd3911d183e2..435d13dd779a66eb855026066695e4048213b842 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -97,6 +97,7 @@
 #include "chrome/browser/ui/webui/chrome_web_ui_controller_factory.h"
 #include "chrome/browser/ui/webui/log_web_ui_url.h"
 #include "chrome/browser/usb/usb_tab_helper.h"
+#include "chrome/browser/webauth/authenticator_web_contents_manager.h"
 #include "chrome/common/channel_info.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_features.h"
@@ -892,6 +893,19 @@ void GetGuestViewDefaultContentSettingRules(
 }
 #endif  // BUILDFLAG(ENABLE_EXTENSIONS)
 
+void CreateAuthenticatorForWebContents(
+    content::RenderFrameHost* render_frame_host,
+    mojo::InterfaceRequest<webauth::mojom::Authenticator> request) {
+  content::WebContents* web_contents =
+      content::WebContents::FromRenderFrameHost(render_frame_host);
+  if (!web_contents) {
+    NOTREACHED();
+    return;
+  }
+  AuthenticatorWebContentsManager::GetOrCreateForWebContents(web_contents)
+      ->CreateAuthenticator(render_frame_host, std::move(request));
+}
+
 void CreateUsbDeviceManager(
     RenderFrameHost* render_frame_host,
     mojo::InterfaceRequest<device::usb::DeviceManager> request) {
@@ -3219,6 +3233,12 @@ void ChromeContentBrowserClient::RegisterRenderFrameMojoInterfaces(
   }
 #endif
 
+  if (AreExperimentalWebPlatformFeaturesEnabled() &&
+      base::FeatureList::IsEnabled(features::kWebAuth)) {
+    registry->AddInterface(
+        base::Bind(&CreateAuthenticatorForWebContents, render_frame_host));
+  }
+
 #if defined(OS_LINUX) || defined(OS_WIN)
   if (!ChromeOriginTrialPolicy().IsFeatureDisabled("WebShare")) {
     registry->AddInterface(base::Bind(&ShareServiceImpl::Create));