Define DevTools content API

content/browser/browser_main_loop.cc

Index: content/browser/browser_main_loop.cc
diff --git a/content/browser/browser_main_loop.cc b/content/browser/browser_main_loop.cc
index 2059d2a040107f26c1a5b6e2d2c5e0515554db80..b708c0a2b6fefc66cc5085b9317516fea98ce4b3 100644
--- a/content/browser/browser_main_loop.cc
+++ b/content/browser/browser_main_loop.cc
@@ -17,6 +17,8 @@
 #include "content/common/sandbox_policy.h"
 #include "content/public/browser/browser_main_parts.h"
 #include "content/public/browser/content_browser_client.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_types.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/main_function_params.h"
 #include "content/public/common/result_codes.h"
@@ -295,6 +297,11 @@ void BrowserMainLoop::RunMainMessageLoopParts(
 
   for (size_t i = 0; i < parts_list_.size(); ++i)
     parts_list_[i]->PostMainMessageLoopRun();
+
+  NotificationService::current()->Notify(
+      NOTIFICATION_MAIN_MESSAGE_LOOP_EXITING,
+      NotificationService::AllSources(),
+      NotificationService::NoDetails());
 }
 
 void BrowserMainLoop::InitializeMainThread() {