Cleanup: Pull some browser keep alive functions into its own file.

chrome/browser/background/background_mode_manager.h

Index: chrome/browser/background/background_mode_manager.h
diff --git a/chrome/browser/background/background_mode_manager.h b/chrome/browser/background/background_mode_manager.h
index 8ced6a73742b85153f7d02ce4f2202564bc21cc3..6471d4f90cda2097667565a2e08e8255cf3ec584 100644
--- a/chrome/browser/background/background_mode_manager.h
+++ b/chrome/browser/background/background_mode_manager.h
@@ -36,6 +36,10 @@ namespace base {
 class CommandLine;
 }
 
+namespace browser_lifetime {
+class ScopedKeepAlive;
+}
+
 typedef std::vector<base::Closure> CommandIdHandlerVector;
 
 // BackgroundModeManager is responsible for switching Chrome into and out of
@@ -413,10 +417,10 @@ class BackgroundModeManager
   // user disables/enables background mode via preferences.
   bool in_background_mode_;
 
-  // Set when we are keeping chrome running during the startup process - this
+  // Set when we are keeping Chrome running during the startup process - this
   // is required when running with the --no-startup-window flag, as otherwise
   // chrome would immediately exit due to having no open windows.
-  bool keep_alive_for_startup_;
+  scoped_ptr<browser_lifetime::ScopedKeepAlive> keep_alive_for_startup_;
 
   // Set to true when Chrome is running with the --keep-alive-for-test flag
   // (used for testing background mode without having to install a background
@@ -427,7 +431,7 @@ class BackgroundModeManager
   bool background_mode_suspended_;
 
   // Set to true when background mode is keeping Chrome alive.
-  bool keeping_alive_;
+  scoped_ptr<browser_lifetime::ScopedKeepAlive> keep_alive_for_background_mode_;
 
   base::WeakPtrFactory<BackgroundModeManager> weak_factory_;