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 1c680d221196c1a0001dfb77db43b509b17be272..6151f8ce1db9a9d9833323036d6a0759ada82327 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -153,6 +153,7 @@
 #include "components/signin/core/common/profile_management_switches.h"
 #include "components/spellcheck/spellcheck_build_features.h"
 #include "components/startup_metric_utils/browser/startup_metric_host_impl.h"
+#include "components/subresource_filter/content/browser/content_subresource_filter_driver_factory.h"

[jochen (gone - plz use gerrit), 2017/06/27 15:10:04]

unrelated?

 #include "components/subresource_filter/content/browser/content_subresource_filter_throttle_manager.h"
 #include "components/task_scheduler_util/browser/initialization.h"
 #include "components/task_scheduler_util/common/variations_util.h"
@@ -161,6 +162,7 @@
 #include "components/url_formatter/url_fixer.h"
 #include "components/variations/variations_associated_data.h"
 #include "components/version_info/version_info.h"
+#include "components/webauth/authenticator_web_contents_manager.h"

[jochen (gone - plz use gerrit), 2017/06/27 15:10:05]

if you don't depend on webauth on android, you can't include the header here
unconditionally

 #include "content/public/browser/browser_child_process_host.h"
 #include "content/public/browser/browser_main_parts.h"
 #include "content/public/browser/browser_ppapi_host.h"
@@ -799,6 +801,17 @@ AppLoadedInTabSource ClassifyAppLoadedInTabSource(
 }
 #endif  // BUILDFLAG(ENABLE_EXTENSIONS)
 
+void CreateAuthenticatorForWebContents(
+    const service_manager::BindSourceInfo& source_info,
+    webauth::mojom::AuthenticatorRequest request,
+    content::RenderFrameHost* render_frame_host) {
+  content::WebContents* web_contents =
+      content::WebContents::FromRenderFrameHost(render_frame_host);
+  DCHECK(web_contents);
+  AuthenticatorWebContentsManager::GetOrCreateForWebContents(web_contents)
+      ->CreateAuthenticator(render_frame_host, std::move(request));
+}
+
 void CreateUsbDeviceManager(const service_manager::BindSourceInfo& source_info,
                             device::mojom::UsbDeviceManagerRequest request,
                             content::RenderFrameHost* render_frame_host) {
@@ -3340,6 +3353,11 @@ void ChromeContentBrowserClient::InitFrameInterfaces() {
       base::Bind(&password_manager::ContentPasswordManagerDriverFactory::
                      BindSensitiveInputVisibilityService));
 
+  if (base::FeatureList::IsEnabled(features::kWebAuth)) {
+    frame_interfaces_parameterized_->AddInterface(
+        base::Bind(&CreateAuthenticatorForWebContents));
+  }
+
 #if defined(OS_ANDROID)
   frame_interfaces_parameterized_->AddInterface(base::Bind(
       &ForwardToJavaWebContentsRegistry<blink::mojom::InstalledAppProvider>));