Disable WebUSB chooser service on chrome extension

chrome/browser/chrome_content_browser_client.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/chrome_content_browser_client.h"
 
 #include <map>
 #include <set>
 #include <utility>
 #include <vector>
@@ skipping 2756 matching lines @@
 #if defined(ENABLE_MOJO_MEDIA)
   registry->AddService(
       base::Bind(&OutputProtectionImpl::Create, render_frame_host));
 #endif  // defined(ENABLE_MOJO_MEDIA)
 }
 
 void ChromeContentBrowserClient::RegisterRenderFrameMojoServices(
     content::ServiceRegistry* registry,
     content::RenderFrameHost* render_frame_host) {
   // WebUSB is an experimental web API. It will only work if the experiment
-  // is enabled and WebUSB feature is enabled.
+  // is enabled and WebUSB feature is enabled and it is not used from chrome
+  // extension.

[Reilly Grant (use Gerrit), 2016/05/11 00:22:44]

Make this a separate sentence:

"It should also not be available to apps and extensions."

[juncai, 2016/05/11 00:32:36]

Done.

   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnableExperimentalWebPlatformFeatures) &&
-      base::FeatureList::IsEnabled(features::kWebUsb)) {
+      base::FeatureList::IsEnabled(features::kWebUsb)
+#if defined(ENABLE_EXTENSIONS)
+      &&
+      !render_frame_host->GetSiteInstance()->GetSiteURL().SchemeIs(
+          extensions::kExtensionScheme)
+#endif
+          ) {
     registry->AddService(
         base::Bind(&CreateUsbDeviceManager, render_frame_host));
     registry->AddService(
         base::Bind(&CreateWebUsbChooserService, render_frame_host));
   }
 
   // Register mojo CredentialManager service only for main frame.
   if (!render_frame_host->GetParent()) {
     registry->AddService(
         base::Bind(&ChromePasswordManagerClient::BindCredentialManager,
@@ skipping 178 matching lines @@
   if (channel <= kMaxDisableEncryptionChannel) {
     static const char* const kWebRtcDevSwitchNames[] = {
       switches::kDisableWebRtcEncryption,
     };
     to_command_line->CopySwitchesFrom(from_command_line,
                                       kWebRtcDevSwitchNames,
                                       arraysize(kWebRtcDevSwitchNames));
   }
 }
 #endif  // defined(ENABLE_WEBRTC)