Refactor CrashDump*Manager to use a shared CrashDumpObserver singleton.

components/crash/content/browser/crash_micro_dump_manager_android.h

-// Copyright 2015 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 COMPONENTS_CRASH_CONTENT_BROWSER_CRASH_MICRO_DUMP_MANAGER_ANDROID_H_
-#define COMPONENTS_CRASH_CONTENT_BROWSER_CRASH_MICRO_DUMP_MANAGER_ANDROID_H_
-
-#include <map>
-#include <memory>
-
-#include "base/files/scoped_file.h"
-#include "base/memory/singleton.h"
-#include "base/memory/weak_ptr.h"
-#include "base/process/kill.h"
-#include "base/sync_socket.h"
-#include "base/synchronization/lock.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
-
-namespace breakpad {
-
-// This class manages behavior of the browser on renderer crashes when
-// microdumps are used for capturing the crash stack.  Normally, in this case
-// the browser doesn't need to do much, because a microdump is written into
-// Android log by the renderer process itself.  However, the browser may need to
-// crash itself on a renderer crash.  Since on Android renderers are not child
-// processes of the browser, it can't access the exit code. Instead, the browser
-// uses a dedicated pipe in order to receive the information about the renderer
-// crash status.
-class CrashMicroDumpManager : public content::NotificationObserver {
- public:
-  // There is only a single instance of CrashMicroDumpManager per browser
-  // process. It needs to be created on the UI thread.
-  static CrashMicroDumpManager* GetInstance();
-
-  // Returns a pipe that should be used to transfer termination cause of
-  // |child_process_id|.
-  base::ScopedFD CreateCrashInfoChannel(int child_process_id);
-
- private:
-  friend struct base::DefaultSingletonTraits<CrashMicroDumpManager>;
-
-  CrashMicroDumpManager();
-  ~CrashMicroDumpManager() override;
-
-  // NotificationObserver implementation:
-  void Observe(int type,
-               const content::NotificationSource& source,
-               const content::NotificationDetails& details) override;
-
-  // Called on child process exit (including crash).
-  void HandleChildTerminationOnFileThread(
-      int child_process_id,
-      base::TerminationStatus termination_status);
-
-  content::NotificationRegistrar notification_registrar_;
-
-  // This map should only be accessed with its lock aquired as it is accessed
-  // from the PROCESS_LAUNCHER, FILE, and UI threads.
-  base::Lock child_process_id_to_pipe_lock_;
-  std::map<int, std::unique_ptr<base::SyncSocket>> child_process_id_to_pipe_;
-  base::WeakPtrFactory<CrashMicroDumpManager> weak_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(CrashMicroDumpManager);
-};
-
-}  // namespace breakpad
-
-#endif  // COMPONENTS_CRASH_CONTENT_BROWSER_CRASH_MICRO_DUMP_MANAGER_ANDROID_H_