Moves ProfilerMetricsProvider to //components/metrics.

chrome/browser/metrics/tracking_synchronizer.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_METRICS_TRACKING_SYNCHRONIZER_H_
-#define CHROME_BROWSER_METRICS_TRACKING_SYNCHRONIZER_H_
-
-#include <map>
-#include <string>
-#include <vector>
-
-#include "base/basictypes.h"
-#include "base/lazy_instance.h"
-#include "base/memory/ref_counted.h"
-#include "base/memory/weak_ptr.h"
-#include "content/public/browser/profiler_subscriber.h"
-
-// This class maintains state that is used to upload profiler data from the
-// various processes, into the browser process. Such transactions are usually
-// instigated by the browser. In general, a process will respond by gathering
-// profiler data, and transmitting the pickled profiler data. We collect the
-// data in asynchronous mode that doesn't block the UI thread.
-//
-// To assure that all the processes have responded, a counter is maintained
-// to indicate the number of pending (not yet responsive) processes. We tag
-// each group of requests with a sequence number. For each group of requests, we
-// create RequestContext object which stores the sequence number, pending
-// processes and the callback_object that needs to be notified when we receive
-// an update from processes. When an update arrives we find the RequestContext
-// associated with sequence number and send the unpickled profiler data to the
-// |callback_object_|.
-
-namespace chrome_browser_metrics {
-
-class TrackingSynchronizerObserver;
-
-class TrackingSynchronizer
-    : public content::ProfilerSubscriber,
-      public base::RefCountedThreadSafe<TrackingSynchronizer> {
- public:
-  // Construction also sets up the global singleton instance. This instance is
-  // used to communicate between the IO and UI thread, and is destroyed only as
-  // the main thread (browser_main) terminates, which means the IO thread has
-  // already completed, and will not need this instance any further.
-  TrackingSynchronizer();
-
-  // Contact all processes, and get them to upload to the browser any/all
-  // changes to profiler data. It calls |callback_object|'s SetData method with
-  // the data received from each sub-process.
-  // This method is accessible on UI thread.
-  static void FetchProfilerDataAsynchronously(
-      const base::WeakPtr<TrackingSynchronizerObserver>& callback_object);
-
-  // ------------------------------------------------------
-  // ProfilerSubscriber methods for browser child processes
-  // ------------------------------------------------------
-
-  // Update the number of pending processes for the given |sequence_number|.
-  // This is called on UI thread.
-  virtual void OnPendingProcesses(int sequence_number,
-                                  int pending_processes,
-                                  bool end) OVERRIDE;
-
- private:
-  friend class base::RefCountedThreadSafe<TrackingSynchronizer>;
-
-  class RequestContext;
-
-  virtual ~TrackingSynchronizer();
-
-  // Send profiler_data back to callback_object_ by calling
-  // DecrementPendingProcessesAndSendData which records that we are waiting
-  // for one less profiler data from renderer or browser child process for the
-  // given sequence number. This method is accessible on UI thread.
-  virtual void OnProfilerDataCollected(
-      int sequence_number,
-      const tracked_objects::ProcessDataSnapshot& profiler_data,
-      int process_type) OVERRIDE;
-
-  // Establish a new sequence_number_, and use it to notify all the processes of
-  // the need to supply, to the browser, their tracking data. It also registers
-  // |callback_object| in |outstanding_requests_| map. Return the
-  // sequence_number_ that was used. This method is accessible on UI thread.
-  int RegisterAndNotifyAllProcesses(
-      const base::WeakPtr<TrackingSynchronizerObserver>& callback_object);
-
-  // It finds the RequestContext for the given |sequence_number| and notifies
-  // the RequestContext's |callback_object_| about the |value|. This is called
-  // whenever we receive profiler data from processes. It also records that we
-  // are waiting for one less profiler data from a process for the given
-  // sequence number. If we have received a response from all renderers and
-  // browser processes, then it calls RequestContext's DeleteIfAllDone to delete
-  // the entry for sequence_number. This method is accessible on UI thread.
-  void DecrementPendingProcessesAndSendData(
-      int sequence_number,
-      const tracked_objects::ProcessDataSnapshot& profiler_data,
-      int process_type);
-
-  // Get a new sequence number to be sent to processes from browser process.
-  // This method is accessible on UI thread.
-  int GetNextAvailableSequenceNumber();
-
-  // We don't track the actual processes that are contacted for an update, only
-  // the count of the number of processes, and we can sometimes time-out and
-  // give up on a "slow to respond" process.  We use a sequence_number to be
-  // sure a response from a process is associated with the current round of
-  // requests. All sequence numbers used are non-negative.
-  // last_used_sequence_number_ is the most recently used number (used to avoid
-  // reuse for a long time).
-  int last_used_sequence_number_;
-
-  DISALLOW_COPY_AND_ASSIGN(TrackingSynchronizer);
-};
-
-}  // namespace chrome_browser_metrics
-
-#endif  // CHROME_BROWSER_METRICS_TRACKING_SYNCHRONIZER_H_