Transmit a X-Chrome-UMA-Enabled bit to Google domains from clients that have UMA enabled.

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_
 #pragma once
 
 #include <string>
 
@@ skipping 165 matching lines @@
   // functions have been provided to assist in common operations.
   void LazyInitialize() const;
 
   // Called when the profile is destroyed.
   void ShutdownOnUIThread();
 
   BooleanPrefMember* enable_referrers() const {
     return &enable_referrers_;
   }
 
+  BooleanPrefMember* enable_metrics() const {
+    return &enable_metrics_;
+  }
+
   ChromeURLDataManagerBackend* chrome_url_data_manager_backend() const {
     return chrome_url_data_manager_backend_.get();
   }
 
   // A ServerBoundCertService object is created by a derived class of
   // ProfileIOData, and the derived class calls this method to set the
   // server_bound_cert_service_ member and transfers ownership to the base
   // class.
   void set_server_bound_cert_service(
       net::ServerBoundCertService* server_bound_cert_service) const;
@@ skipping 69 matching lines @@
 
   // Tracks whether or not we've been lazily initialized.
   mutable bool initialized_;
 
   // Data from the UI thread from the Profile, used to initialize ProfileIOData.
   // Deleted after lazy initialization.
   mutable scoped_ptr<ProfileParams> profile_params_;
 
   // Member variables which are pointed to by the various context objects.
   mutable BooleanPrefMember enable_referrers_;
+  mutable BooleanPrefMember enable_metrics_;
   mutable BooleanPrefMember clear_local_state_on_exit_;
   mutable BooleanPrefMember safe_browsing_enabled_;
   // TODO(marja): Remove session_startup_pref_ if no longer needed.
   mutable IntegerPrefMember session_startup_pref_;
 
   // Pointed to by NetworkDelegate.
   mutable scoped_ptr<policy::URLBlacklistManager> url_blacklist_manager_;
 
   // Pointed to by URLRequestContext.
   mutable scoped_ptr<ChromeURLDataManagerBackend>
@@ skipping 31 matching lines @@
   // One AppRequestContext per isolated app.
   mutable AppRequestContextMap app_request_context_map_;
 
   // TODO(jhawkins): Remove once crbug.com/102004 is fixed.
   bool initialized_on_UI_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileIOData);
 };
 
 #endif  // CHROME_BROWSER_PROFILES_PROFILE_IO_DATA_H_