Run the later parts of startup as UI thread tasks

content/public/browser/browser_main_runner.h

Index: content/public/browser/browser_main_runner.h
diff --git a/content/public/browser/browser_main_runner.h b/content/public/browser/browser_main_runner.h
index 4340687796ec32a4c939cfd00ce8ba9b276202d4..f907ae4e1fceca3e91871f630dae379ebc73a037 100644
--- a/content/public/browser/browser_main_runner.h
+++ b/content/public/browser/browser_main_runner.h
@@ -6,7 +6,9 @@
 #define CONTENT_PUBLIC_BROWSER_BROWSER_MAIN_RUNNER_H_
 
 #include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
 #include "content/common/content_export.h"
+#include "content/public/common/startup_task_runner.h"
 
 namespace content {
 
@@ -22,7 +24,9 @@ class CONTENT_EXPORT BrowserMainRunner {
 
   // Initialize all necessary browser state. The |parameters| values will be
   // copied.
-  virtual int Initialize(const content::MainFunctionParams& parameters) = 0;
+  virtual int Initialize(
+      const content::MainFunctionParams& parameters,
+      const scoped_refptr<StartupTaskRunner>& task_runner) = 0;
 
   // Perform the default run logic.
   virtual int Run() = 0;