Add a notification observer for the first tab load for Chrome OS.
It simply records the uptime into the tmp directory for metrics collection

BUG=none
TEST=none
Original review: http://codereview.chromium.org/548044
Patch by [email protected]

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@36876 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index 76c622bc..4f5c8375 100755
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -251,6 +251,7 @@
         'browser/chrome_plugin_host.h',
         'browser/chrome_thread.cc',
         'browser/chrome_thread.h',
+	'browser/chromeos/browser_notification_observers.cc',
         'browser/chromeos/browser_extenders.cc',
         'browser/chromeos/chromeos_browser_view.cc',
         'browser/chromeos/chromeos_browser_view.h',