Remove all blimp engine code

blimp/engine/app/blimp_stability_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 BLIMP_ENGINE_APP_BLIMP_STABILITY_METRICS_PROVIDER_H_
-#define BLIMP_ENGINE_APP_BLIMP_STABILITY_METRICS_PROVIDER_H_
-
-#include "base/gtest_prod_util.h"
-#include "base/macros.h"
-#include "base/metrics/user_metrics.h"
-#include "base/process/kill.h"
-#include "components/metrics/metrics_provider.h"
-#include "components/metrics/stability_metrics_helper.h"
-#include "content/public/browser/browser_child_process_observer.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
-
-class PrefService;
-
-// BlimpStabilityMetricsProvider gathers and logs Blimp-specific stability-
-// related metrics.
-class BlimpStabilityMetricsProvider
-    : public metrics::MetricsProvider,
-      public content::BrowserChildProcessObserver,
-      public content::NotificationObserver {
- public:
-  explicit BlimpStabilityMetricsProvider(PrefService* local_state);
-  ~BlimpStabilityMetricsProvider() override;
-
-  // metrics::MetricsDataProvider:
-  void OnRecordingEnabled() override;
-  void OnRecordingDisabled() override;
-  void ProvideStabilityMetrics(
-      metrics::SystemProfileProto* system_profile_proto) override;
-  void ClearSavedStabilityMetrics() override;
-
- private:
-  FRIEND_TEST_ALL_PREFIXES(BlimpStabilityMetricsProviderTest,
-                           BrowserChildProcessObserver);
-  FRIEND_TEST_ALL_PREFIXES(BlimpStabilityMetricsProviderTest,
-                           NotificationObserver);
-
-  // content::NotificationObserver:
-  void Observe(int type,
-               const content::NotificationSource& source,
-               const content::NotificationDetails& details) override;
-
-  // content::BrowserChildProcessObserver:
-  void BrowserChildProcessCrashed(
-      const content::ChildProcessData& data,
-      int exit_code) override;
-
-  metrics::StabilityMetricsHelper helper_;
-
-  // Registrar for receiving stability-related notifications.
-  content::NotificationRegistrar registrar_;
-
-  DISALLOW_COPY_AND_ASSIGN(BlimpStabilityMetricsProvider);
-};
-
-#endif  // BLIMP_ENGINE_APP_BLIMP_STABILITY_METRICS_PROVIDER_H_