Histogram the scheme of an origin on the 1st navigation to it.

chrome/browser/profiles/profile_io_data.h

 // 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.
 
 #ifndef CHROME_BROWSER_PROFILES_PROFILE_IO_DATA_H_
 #define CHROME_BROWSER_PROFILES_PROFILE_IO_DATA_H_
 
 #include <stdint.h>
 
 #include <map>
+#include <set>
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/synchronization/lock.h"
@@ skipping 176 matching lines @@
 
   bool use_system_key_slot() const { return use_system_key_slot_; }
 #endif
 
   Profile::ProfileType profile_type() const {
     return profile_type_;
   }
 
   bool IsOffTheRecord() const;
 
+  // Used when deciding whether or not to record
+  // Navigation.SchemePerUniqueOrigin[OTR]. Uses |origins_seen_|.
+  bool HaveAlreadySeenOrigin(const url::Origin& origin);
+
   IntegerPrefMember* incognito_availibility() const {
     return &incognito_availibility_pref_;
   }
 
   chrome_browser_net::ResourcePrefetchPredictorObserver*
       resource_prefetch_predictor_observer() const {
     return resource_prefetch_predictor_observer_.get();
   }
 
   policy::PolicyHeaderIOHelper* policy_header_helper() const {
@@ skipping 373 matching lines @@
       extension_throttle_manager_;
 #endif
 
   mutable DevToolsNetworkControllerHandle network_controller_handle_;
 
   // TODO(jhawkins): Remove once crbug.com/102004 is fixed.
   bool initialized_on_UI_thread_;
 
   const Profile::ProfileType profile_type_;
 
+  // Used by |HaveAlreadySeenOrigin|.
+  std::set<url::Origin> origins_seen_;
+
   DISALLOW_COPY_AND_ASSIGN(ProfileIOData);
 };
 
 #endif  // CHROME_BROWSER_PROFILES_PROFILE_IO_DATA_H_