Refactor CrashDump*Manager to use a shared CrashDumpObserver singleton.

content/shell/browser/shell_browser_main_parts.h

Index: content/shell/browser/shell_browser_main_parts.h
diff --git a/content/shell/browser/shell_browser_main_parts.h b/content/shell/browser/shell_browser_main_parts.h
index e245404a09471fbd8bef69a16c53abe158b62e38..0cd3f1250333e3004c50dce5c3f8d064f6cad482 100644
--- a/content/shell/browser/shell_browser_main_parts.h
+++ b/content/shell/browser/shell_browser_main_parts.h
@@ -61,9 +61,6 @@ class ShellBrowserMainParts : public BrowserMainParts {
   }
 
  private:
-#if defined(OS_ANDROID)
-  std::unique_ptr<breakpad::CrashDumpManager> crash_dump_manager_;
-#endif
   std::unique_ptr<net::NetLog> net_log_;
   std::unique_ptr<ShellBrowserContext> browser_context_;
   std::unique_ptr<ShellBrowserContext> off_the_record_browser_context_;
@@ -72,6 +69,10 @@ class ShellBrowserMainParts : public BrowserMainParts {
   const MainFunctionParams parameters_;
   bool run_message_loop_;
 
+#if defined(OS_ANDROID)
+  scoped_refptr<breakpad::CrashDumpManager> crash_dump_manager_;
+#endif
+
   DISALLOW_COPY_AND_ASSIGN(ShellBrowserMainParts);
 };