Provide the DeviceManager service to the renderer directly, no app.

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 dd26039d02ff83f3b1baad445e45531bb99f2ea0..f4e9ff035aff11c21214511f84833314c2cfdc95 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -133,8 +133,6 @@
 #include "content/public/common/service_registry.h"
 #include "content/public/common/url_utils.h"
 #include "content/public/common/web_preferences.h"
-#include "device/devices_app/public/cpp/constants.h"
-#include "device/devices_app/public/cpp/devices_app_factory.h"
 #include "gin/v8_initializer.h"
 #include "mojo/application/public/cpp/application_delegate.h"
 #include "net/base/mime_util.h"
@@ -263,6 +261,7 @@
 
 #if !defined(OS_ANDROID) && !defined(OS_IOS)
 #include "chrome/browser/usb/web_usb_permission_provider.h"
+#include "device/devices_app/usb/device_manager_impl.h"
 #endif
 
 using base::FileDescriptor;
@@ -623,6 +622,18 @@ void GetGuestViewDefaultContentSettingRules(
 }
 #endif  // defined(ENABLE_EXTENSIONS)
 
+void CreateUsbDeviceManager(
+    RenderFrameHost* render_frame_host,
+    mojo::InterfaceRequest<device::usb::DeviceManager> request) {

[Ken Rockot(use gerrit already), 2015/09/29 00:22:53]

you should include "device/usb/public/interfaces/device_manager.mojom"
regardless of platform

+#if !defined(OS_ANDROID) && !defined(OS_IOS)
+  device::usb::PermissionProviderPtr permission_provider;
+  WebUSBPermissionProvider::Create(render_frame_host,
+                                   mojo::GetProxy(&permission_provider));
+  device::usb::DeviceManagerImpl::Create(permission_provider.Pass(),
+                                         request.Pass());
+#endif  // !defined(OS_ANDROID) && !defined(OS_IOS)
+}
+
 }  // namespace
 
 ChromeContentBrowserClient::ChromeContentBrowserClient()
@@ -2544,19 +2555,12 @@ void ChromeContentBrowserClient::RegisterFrameMojoShellServices(
       base::Bind(&chromeos::attestation::PlatformVerificationImpl::Create,
                  render_frame_host));
 #endif
-#if !defined(OS_ANDROID) && !defined(OS_IOS)
-  registry->AddService(
-      base::Bind(&WebUSBPermissionProvider::Create, render_frame_host));
-#endif
 }
 
-void ChromeContentBrowserClient::RegisterInProcessMojoApplications(
-    StaticMojoApplicationMap* apps) {
-#if !defined(OS_ANDROID) && !defined(OS_IOS)
-  apps->insert(std::make_pair(GURL(device::kDevicesMojoAppUrl),
-                              base::Bind(&device::DevicesAppFactory::CreateApp,
-                                         base::ThreadTaskRunnerHandle::Get())));
-#endif
+void ChromeContentBrowserClient::RegisterRenderFrameMojoServices(
+    content::ServiceRegistry* registry,
+    content::RenderFrameHost* render_frame_host) {
+  registry->AddService(base::Bind(&CreateUsbDeviceManager, render_frame_host));
 }
 
 void ChromeContentBrowserClient::OpenURL(