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

chrome/browser/lifetime/application_lifetime.h

Index: chrome/browser/lifetime/application_lifetime.h
diff --git a/chrome/browser/lifetime/application_lifetime.h b/chrome/browser/lifetime/application_lifetime.h
index 3cf18549cd37768132f3af62cd9e806c18beded3..885ef8d111d288dc354bd83b1521318750d96ce8 100644
--- a/chrome/browser/lifetime/application_lifetime.h
+++ b/chrome/browser/lifetime/application_lifetime.h
@@ -82,21 +82,6 @@ void CloseAllBrowsers();
 // Begins shutdown of the application when the desktop session is ending.
 void SessionEnding();
 
-// Tells the BrowserList to keep the application alive after the last Browser
-// closes. This is implemented as a count, so callers should pair their calls
-// to IncrementKeepAliveCount() with matching calls to DecrementKeepAliveCount()
-// when they no
-// longer need to keep the application running.
-void IncrementKeepAliveCount();
-
-// Stops keeping the application alive after the last Browser is closed.
-// Should match a previous call to IncrementKeepAliveCount().
-void DecrementKeepAliveCount();
-
-// Returns true if application will continue running after the last Browser
-// closes.
-bool WillKeepAlive();
-
 // Emits APP_TERMINATING notification. It is guaranteed that the
 // notification is sent only once.
 void NotifyAppTerminating();
@@ -116,9 +101,6 @@ void HandleAppExitingForPlatform();
 // last browser window is being closed.
 bool ShouldStartShutdown(Browser* browser);
 
-// Disable browser shutdown for unit tests.
-void DisableShutdownForTesting(bool disable_shutdown_for_testing);
-
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_LIFETIME_APPLICATION_LIFETIME_H_