[webnfc] Add WebNFC feature flag

content/public/android/java/src/org/chromium/content/browser/InterfaceRegistrarImpl.java

 // Copyright 2016 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.
 
 package org.chromium.content.browser;
 
 import android.content.Context;
 
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
@@ skipping 62 matching lines @@
             registry.addInterface(AndroidOverlayProvider.MANAGER,
                     new AndroidOverlayProviderImpl.Factory(applicationContext));
             // TODO(avayvod): Register the PresentationService implementation here.
         }
     }
 
     private static class ContentWebContentsInterfaceRegistrar
             implements InterfaceRegistrar<WebContents> {
         @Override
         public void registerInterfaces(InterfaceRegistry registry, final WebContents webContents) {
-            registry.addInterface(Nfc.MANAGER, new NfcFactory(webContents));
+            if (ContentFeatureList.isEnabled(ContentFeatureList.WEB_NFC)) {
+                registry.addInterface(Nfc.MANAGER, new NfcFactory(webContents));
+            }
         }
     }
 
     private static class ContentRenderFrameHostInterfaceRegistrar
             implements InterfaceRegistrar<RenderFrameHost> {
         @Override
         public void registerInterfaces(
                 InterfaceRegistry registry, final RenderFrameHost renderFrameHost) {
             registry.addInterface(
                     InstalledAppProvider.MANAGER, new InstalledAppProviderFactory(renderFrameHost));
         }
     }
 }