Run the later parts of startup as UI thread tasks

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 d7553cc1012b087b98ae0f232a879be3c0c12dae..4056b8aedfb4fda7d41c3fcab2371d02b10e161e 100644
--- a/content/browser/browser_main_loop.cc
+++ b/content/browser/browser_main_loop.cc
@@ -44,6 +44,7 @@
 #include "content/public/common/content_switches.h"
 #include "content/public/common/main_function_params.h"
 #include "content/public/common/result_codes.h"
+#include "content/public/common/startup_task_runner.h"
 #include "crypto/nss_util.h"
 #include "media/audio/audio_manager.h"
 #include "media/base/media.h"
@@ -471,8 +472,8 @@ void BrowserMainLoop::MainMessageLoopStart() {
   }
 }
 
-void BrowserMainLoop::CreateThreads() {
-  TRACE_EVENT0("startup", "BrowserMainLoop::CreateThreads")
+
+void BrowserMainLoop::PreCreateThreads() {
 
   if (parts_) {
     TRACE_EVENT0("startup",
@@ -497,9 +498,35 @@ void BrowserMainLoop::CreateThreads() {
   if (parsed_command_line_.HasSwitch(switches::kSingleProcess))
     RenderProcessHost::SetRunRendererInProcess(true);
 #endif
+}
+
+void BrowserMainLoop::CreateStartupTasks(
+    const scoped_refptr<StartupTaskRunner>& task_runner) {
+  TRACE_EVENT0("startup", "BrowserMainLoop::CreateStartupTasks")
+
+  task_runner->SetProxy(base::MessageLoop::current()->message_loop_proxy());
+
+  base::Closure pre_create_threads =
+      base::Bind(&BrowserMainLoop::PreCreateThreads, base::Unretained(this));
+  task_runner->AddTask(pre_create_threads);
 
-  if (result_code_ > 0)
-    return;
+  base::Closure create_threads =
+      base::Bind(&BrowserMainLoop::CreateThreads, base::Unretained(this));
+  task_runner->AddTask(create_threads);
+
+  base::Closure browser_thread_started = base::Bind(
+      &BrowserMainLoop::BrowserThreadsStarted, base::Unretained(this));
+  task_runner->AddTask(browser_thread_started);
+
+  base::Closure pre_main_message_loop_run = base::Bind(
+      &BrowserMainLoop::PreMainMessageLoopRun, base::Unretained(this));
+  task_runner->AddTask(pre_main_message_loop_run);
+
+  task_runner->StartRunningTasks();
+}
+
+void BrowserMainLoop::CreateThreads() {
+  TRACE_EVENT0("startup", "BrowserMainLoop::CreateThreads");
 
   base::Thread::Options default_options;
   base::Thread::Options io_message_loop_options;
@@ -585,13 +612,9 @@ void BrowserMainLoop::CreateThreads() {
 
   }
 
-#if !defined(OS_IOS)
-  indexed_db_thread_.reset(new base::Thread("IndexedDB"));
-  indexed_db_thread_->Start();
-#endif
-
-  BrowserThreadsStarted();
+}
 
+void BrowserMainLoop::PreMainMessageLoopRun() {
   if (parts_) {
     TRACE_EVENT0("startup",
         "BrowserMainLoop::CreateThreads:PreMainMessageLoopRun");
@@ -753,6 +776,12 @@ void BrowserMainLoop::InitializeMainThread() {
 
 void BrowserMainLoop::BrowserThreadsStarted() {
   TRACE_EVENT0("startup", "BrowserMainLoop::BrowserThreadsStarted")
+
+#if !defined(OS_IOS)
+  indexed_db_thread_.reset(new base::Thread("IndexedDB"));
+  indexed_db_thread_->Start();
+#endif
+
 #if defined(OS_ANDROID)
   // Up the priority of anything that touches with display tasks
   // (this thread is UI thread, and io_thread_ is for IPCs).