Revert "Create and pass shared-histogram-allocator from browser to renderer."

chrome/browser/metrics/subprocess_metrics_provider.h

-// Copyright 2016 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_SUBPROCESS_METRICS_PROVIDER_H_
-#define CHROME_BROWSER_METRICS_SUBPROCESS_METRICS_PROVIDER_H_
-
-#include <memory>
-#include <set>
-
-#include "base/gtest_prod_util.h"
-#include "base/id_map.h"
-#include "base/scoped_observer.h"
-#include "base/threading/thread_checker.h"
-#include "components/metrics/metrics_provider.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
-#include "content/public/browser/render_process_host_observer.h"
-
-namespace base {
-class PersistentHistogramAllocator;
-class SharedPersistentMemoryAllocator;
-}
-
-// SubprocessMetricsProvider gathers and logs histograms stored in shared
-// memory segments between processes.
-class SubprocessMetricsProvider : public metrics::MetricsProvider,
-                                  public content::NotificationObserver,
-                                  public content::RenderProcessHostObserver {
- public:
-  SubprocessMetricsProvider();
-  ~SubprocessMetricsProvider() override;
-
- private:
-  friend class SubprocessMetricsProviderTest;
-
-  // Indicates subprocess to be monitored with unique id for later reference.
-  // Metrics reporting will read histograms from it and upload them to UMA.
-  void RegisterSubprocessAllocator(
-      int id,
-      std::unique_ptr<base::PersistentHistogramAllocator> allocator);
-
-  // Indicates that a subprocess has exited and is thus finished with the
-  // allocator it was using.
-  void DeregisterSubprocessAllocator(int id);
-
-  // Report all histograms of a given allocator to the snapshot-manager.
-  void RecordHistogramSnapshotsFromAllocator(
-      base::HistogramSnapshotManager* snapshot_manager,
-      int id,
-      base::PersistentHistogramAllocator* allocator);
-
-  // metrics::MetricsProvider:
-  void OnRecordingEnabled() override;
-  void OnRecordingDisabled() override;
-  void RecordHistogramSnapshots(
-      base::HistogramSnapshotManager* snapshot_manager) override;
-
-  // content::NotificationObserver:
-  void Observe(int type,
-               const content::NotificationSource& source,
-               const content::NotificationDetails& details) override;
-
-  // content::RenderProcessHostObserver:
-  void RenderProcessReady(content::RenderProcessHost* host) override;
-  void RenderProcessExited(content::RenderProcessHost* host,
-                           base::TerminationStatus status,
-                           int exit_code) override;
-  void RenderProcessHostDestroyed(content::RenderProcessHost* host) override;
-
-  base::ThreadChecker thread_checker_;
-
-  // Object for registing notification requests.
-  content::NotificationRegistrar registrar_;
-
-  // All of the shared-persistent-allocators for known sub-processes.
-  using AllocatorByIdMap =
-      IDMap<base::PersistentHistogramAllocator, IDMapOwnPointer, int>;
-  AllocatorByIdMap allocators_by_id_;
-
-  // Allocators that are no longer attached to a subprocess, to be released
-  // once the last data contained therein has been reported.
-  std::vector<std::unique_ptr<base::PersistentHistogramAllocator>>
-      allocators_to_release_;
-
-  // Track all observed render processes to un-observe them on exit.
-  ScopedObserver<content::RenderProcessHost, SubprocessMetricsProvider>
-      scoped_observer_;
-
-  // Flag indicating if metrics recording is enabled. Allocators will not
-  // live past the death of the subprocess if it is not.
-  bool metrics_recording_enabled_ = false;
-
-  DISALLOW_COPY_AND_ASSIGN(SubprocessMetricsProvider);
-};
-
-#endif  // CHROME_BROWSER_METRICS_SUBPROCESS_METRICS_PROVIDER_H_