Refactor CrashDump*Manager to use a shared CrashDumpObserver singleton.

chrome/browser/chrome_browser_main_android.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_CHROME_BROWSER_MAIN_ANDROID_H_
 #define CHROME_BROWSER_CHROME_BROWSER_MAIN_ANDROID_H_
 
 #include "base/macros.h"
 #include "chrome/browser/android/chrome_backup_watcher.h"
 #include "chrome/browser/chrome_browser_main.h"
 
-namespace breakpad {
-class CrashDumpManager;
-}
-
 class ChromeBrowserMainPartsAndroid : public ChromeBrowserMainParts {
  public:
   explicit ChromeBrowserMainPartsAndroid(
       const content::MainFunctionParams& parameters);
   ~ChromeBrowserMainPartsAndroid() override;
 
   // content::BrowserMainParts overrides.
   int PreCreateThreads() override;
   void PostProfileInit() override;
   void PreEarlyInitialization() override;
 
   // ChromeBrowserMainParts overrides.
   void PostBrowserStart() override;
   void ShowMissingLocaleMessageBox() override;
 
  private:
   std::unique_ptr<base::MessageLoop> main_message_loop_;
-  std::unique_ptr<breakpad::CrashDumpManager> crash_dump_manager_;
   std::unique_ptr<chrome::android::ChromeBackupWatcher> backup_watcher_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeBrowserMainPartsAndroid);
 };
 
 #endif  // CHROME_BROWSER_CHROME_BROWSER_MAIN_ANDROID_H_