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 sosa@chromium.org

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@36876 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 98 insertions, 0 deletions

diff --git a/chrome/browser/browser_init.cc b/chrome/browser/browser_init.cc
index 9406d6d..0a74de0 100644
--- a/chrome/browser/browser_init.cc
+++ b/chrome/browser/browser_init.cc
@@ -57,6 +57,7 @@
 #endif
 
 #if defined(OS_CHROMEOS)
+#include "chrome/browser/chromeos/browser_notification_observers.h"
 #include "chrome/browser/chromeos/gview_request_interceptor.h"
 #include "chrome/browser/chromeos/mount_library.h"
 #include "chrome/browser/chromeos/usb_mount_observer.h"
@@ -312,6 +313,14 @@ bool LaunchBrowser(const CommandLine& command_line, Profile* profile,
   in_startup = process_startup;
   DCHECK(profile);
 
+  // This forces the creation of the initial tavb notification observer
+  // singleton.  It must be created before browser launch to catch first tab
+  // load.
+#if defined(OS_CHROMEOS)
+  if (process_startup)
+    chromeos::InitialTabNotificationObserver::Get();
+#endif
+
   // Continue with the off-the-record profile from here on if --incognito
   if (command_line.HasSwitch(switches::kIncognito))
     profile = profile->GetOffTheRecordProfile();
diff --git a/chrome/browser/chromeos/browser_notification_observers.cc b/chrome/browser/chromeos/browser_notification_observers.cc
new file mode 100644
index 0000000..e47c452
--- /dev/null
+++ b/chrome/browser/chromeos/browser_notification_observers.cc
@@ -0,0 +1,45 @@
+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/chromeos/browser_notification_observers.h"
+
+#include "chrome/browser/chrome_thread.h"
+#include "chrome/common/notification_service.h"
+
+namespace {
+
+// Static function that records uptime in /proc/uptime to tmp for metrics use.
+void RecordUptime() {
+  system("cat /proc/uptime > /tmp/uptime-chrome-first-render &");
+}
+
+}  // namespace
+
+namespace chromeos {
+
+InitialTabNotificationObserver::InitialTabNotificationObserver() {
+  registrar_.Add(this, NotificationType::LOAD_START,
+                 NotificationService::AllSources());
+}
+
+InitialTabNotificationObserver::~InitialTabNotificationObserver() {
+}
+
+void InitialTabNotificationObserver::Observe(
+    NotificationType type,
+    const NotificationSource& source,
+    const NotificationDetails& details) {
+  // Only log for first tab to render.  Make sure this is only done once.
+  if (type == NotificationType::LOAD_START &&
+      num_tabs_.GetNext() == 0) {
+    // If we can't post it, it doesn't matter.
+    ChromeThread::PostTask(
+        ChromeThread::FILE, FROM_HERE,
+        NewRunnableFunction(RecordUptime));
+    registrar_.Remove(this, NotificationType::LOAD_START,
+                      NotificationService::AllSources());
+  }
+}
+
+}  // namespace chromeos
diff --git a/chrome/browser/chromeos/browser_notification_observers.h b/chrome/browser/chromeos/browser_notification_observers.h
new file mode 100644
index 0000000..91c95b9
--- /dev/null
+++ b/chrome/browser/chromeos/browser_notification_observers.h
@@ -0,0 +1,43 @@
+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_CHROMEOS_BROWSER_NOTIFICATION_OBSERVERS_H_
+#define CHROME_BROWSER_CHROMEOS_BROWSER_NOTIFICATION_OBSERVERS_H_
+
+#include "base/atomic_sequence_num.h"
+#include "base/singleton.h"
+#include "chrome/common/notification_observer.h"
+#include "chrome/common/notification_registrar.h"
+#include "chrome/common/notification_source.h"
+#include "chrome/common/notification_type.h"
+
+// Global notification observers for chrome os.
+namespace chromeos {
+
+// Notification observer to log the initial time of when the first tab
+// page is rendered for Chrome OS.
+class InitialTabNotificationObserver : public NotificationObserver {
+ public:
+  InitialTabNotificationObserver();
+  virtual ~InitialTabNotificationObserver();
+
+  static InitialTabNotificationObserver* Get() {
+    return Singleton<InitialTabNotificationObserver>::get();
+  }
+
+  // NotificationObserver implementation.
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details);
+
+ private:
+  NotificationRegistrar registrar_;
+  base::AtomicSequenceNumber num_tabs_;
+
+  DISALLOW_COPY_AND_ASSIGN(InitialTabNotificationObserver);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_BROWSER_NOTIFICATION_OBSERVERS_H_
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index 76c622b..4f5c837 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',