Refactor CrashDump*Manager to use a shared CrashDumpObserver singleton.

android_webview/browser/aw_browser_main_parts.h

Index: android_webview/browser/aw_browser_main_parts.h
diff --git a/android_webview/browser/aw_browser_main_parts.h b/android_webview/browser/aw_browser_main_parts.h
index 8d4671f6dd6f761efc697d6d24495482530296f0..2b7896c180ae46bdb63c7c56e3626590346e0216 100644
--- a/android_webview/browser/aw_browser_main_parts.h
+++ b/android_webview/browser/aw_browser_main_parts.h
@@ -9,6 +9,7 @@
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
+#include "base/memory/ref_counted.h"
 #include "content/public/browser/browser_main_parts.h"
 
 namespace base {
@@ -18,6 +19,7 @@ class MessageLoop;
 namespace android_webview {
 
 class AwBrowserContext;
+class AwBrowserTerminator;
 class AwContentBrowserClient;
 
 class AwBrowserMainParts : public content::BrowserMainParts {
@@ -34,6 +36,7 @@ class AwBrowserMainParts : public content::BrowserMainParts {
  private:
   // Android specific UI MessageLoop.
   std::unique_ptr<base::MessageLoop> main_message_loop_;
+  scoped_refptr<AwBrowserTerminator> aw_browser_terminator_;
 
   AwContentBrowserClient* browser_client_;