Move the Chrome Variations HTTP header helper file into c/b/metrics/variations, and fix up lock beh…

chrome/browser/chrome_metrics_helper.h

Index: chrome/browser/chrome_metrics_helper.h
diff --git a/chrome/browser/chrome_metrics_helper.h b/chrome/browser/chrome_metrics_helper.h
deleted file mode 100644
index 268b55cccb5c440ce382bf34e8900c930d7979b3..0000000000000000000000000000000000000000
--- a/chrome/browser/chrome_metrics_helper.h
+++ /dev/null
@@ -1,83 +0,0 @@
-// 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_CHROME_METRICS_HELPER_H_
-#define CHROME_BROWSER_CHROME_METRICS_HELPER_H_
-
-#include <set>
-#include <string>
-
-#include "base/basictypes.h"
-#include "base/metrics/field_trial.h"
-#include "base/synchronization/lock.h"
-#include "chrome/common/metrics/variations/variation_ids.h"
-
-namespace content {
-class ResourceContext;
-}
-
-namespace net {
-class HttpRequestHeaders;
-}
-
-class GURL;
-class Profile;
-class ProfileIOData;
-
-template <typename T> struct DefaultSingletonTraits;
-
-// A helper class for maintaining Chrome experiments and metrics state
-// transmitted in custom HTTP request headers.
-// This class is a thread-safe singleton.
-class ChromeMetricsHelper : base::FieldTrialList::Observer {
- public:
-  static ChromeMetricsHelper* GetInstance();
-
-  // Adds Chrome experiment and metrics state as custom headers to |headers|.
-  // Some headers may not be set given the |incognito| mode or whether
-  // the user has |uma_enabled|.  Also, we never transmit headers to non-Google
-  // sites, which is checked based on the destination |url|.
-  void AppendHeaders(const GURL& url,
-                     bool incognito,
-                     bool uma_enabled,
-                     net::HttpRequestHeaders* headers);
-
- private:
-  friend struct DefaultSingletonTraits<ChromeMetricsHelper>;
-
-  ChromeMetricsHelper();
-  virtual ~ChromeMetricsHelper();
-
-  // base::FieldTrialList::Observer implementation.
-  // This will add the variation ID associated with |trial_name| and
-  // |group_name| to the variation ID cache.
-  virtual void OnFieldTrialGroupFinalized(
-      const std::string& trial_name,
-      const std::string& group_name) OVERRIDE;
-
-  // Prepares the variation IDs cache with initial values if not already done.
-  // This method also registers the caller with the FieldTrialList to receive
-  // new variation IDs.
-  void InitVariationIDsCacheIfNeeded();
-
-  // Takes whatever is currently in |variation_ids_set_| and recreates
-  // |variation_ids_header_| with it.
-  void UpdateVariationIDsHeaderValue();
-
-  // Guards |variation_ids_cache_initialized_|, |variation_ids_set_| and
-  // |variation_ids_header_|.
-  base::Lock lock_;
-
-  // Whether or not we've initialized the cache.
-  bool variation_ids_cache_initialized_;
-
-  // Keep a cache of variation IDs that are transmitted in headers to Google.
-  // This consists of a list of valid IDs, and the actual transmitted header.
-  std::set<chrome_variations::VariationID> variation_ids_set_;
-  std::string variation_ids_header_;
-
-  DISALLOW_COPY_AND_ASSIGN(ChromeMetricsHelper);
-};
-
-#endif  // CHROME_BROWSER_CHROME_METRICS_HELPER_H_