Add a "guard" content settings type for chooser permissions.

chrome/browser/usb/usb_chooser_context.cc

 // Copyright 2015 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/usb/usb_chooser_context.h"
 
 #include "base/stl_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/values.h"
 #include "device/core/device_client.h"
@@ skipping 31 matching lines @@
       return device_dict;
     }
   }
   return nullptr;
 }
 
 }  // namespace
 
 UsbChooserContext::UsbChooserContext(Profile* profile)
     : ChooserContextBase(profile,
+                         CONTENT_SETTINGS_TYPE_USB,
                          CONTENT_SETTINGS_TYPE_USB_CHOOSER_DATA),
       observer_(this) {
   usb_service_ = device::DeviceClient::Get()->GetUsbService();
   if (usb_service_)
     observer_.Add(usb_service_);
 }
 
 UsbChooserContext::~UsbChooserContext() {}
 
 void UsbChooserContext::GrantDevicePermission(const GURL& requesting_origin,
@@ skipping 56 matching lines @@
 bool UsbChooserContext::IsValidObject(const base::DictionaryValue& object) {
   return object.size() == 4 && object.HasKey(kDeviceNameKey) &&
          object.HasKey(kVendorIdKey) && object.HasKey(kProductIdKey) &&
          object.HasKey(kSerialNumberKey);
 }
 
 void UsbChooserContext::OnDeviceRemoved(scoped_refptr<UsbDevice> device) {
   for (auto& map_entry : ephemeral_devices_)
     map_entry.second.erase(device->guid());
 }