Create an instance of AtExitManager before relaunching the browser on Windows.  This is needed for two reasons: 1) The RelaunchChromeBrowserWithNewCommandLineIfNeeded() code path on Windows invokes Singleton<PathData>::get()    to get the module.  This in turn requires an  instance of AtExitManager to be present, as it manages the    lifetime of singletons. 2) The point at which the RelaunchChromeBrowserWithNewCommandLineIfNeeded() is invoked we return from    ChromeMain and thus the instance of AtExitManager that belongs to chrome.dll is already deleted. 3) Note that there is another instance of AtExitManager that's instantiated in wWinMain() that's still alive.    But the scope of that is in chrome.exe and not chrome.dll, and hence is not visible to the code in    RelaunchChromeBrowserWithNewCommandLineIfNeeded().
Create an instance of AtExitManager before relaunching the browser on Windows.  This is needed for two reasons:
1) The RelaunchChromeBrowserWithNewCommandLineIfNeeded() code path on Windows invokes Singleton<PathData>::get()
   to get the module.  This in turn requires an  instance of AtExitManager to be present, as it manages the
   lifetime of singletons.
2) The point at which the RelaunchChromeBrowserWithNewCommandLineIfNeeded() is invoked we return from
   ChromeMain and thus the instance of AtExitManager that belongs to chrome.dll is already deleted.
3) Note that there is another instance of AtExitManager that's instantiated in wWinMain() that's still alive.
   But the scope of that is in chrome.exe and not chrome.dll, and hence is not visible to the code in
   RelaunchChromeBrowserWithNewCommandLineIfNeeded().

BUG=none 
TEST=On Windows - Change BrowserProcessImpl::StartAutoupdateTimer() function to 
change the timer from 6hrs to 30 seconds. Build and run chrome with 
--no-startup-window and --keep-alive-for-test flags. Copy chrome.exe to new_chrome.exe 
to fake an update. Wait for 30 seconds and verify that the browser shuts 
down and restarts.  Also verify that new_chrome.exe is deleted and there is an old_chrome.exe.

Review URL: http://codereview.chromium.org/3104037

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@57756 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser