Add function to CancelableTaskTracker and convert BootTimeLoader (take 2)

chrome/browser/chromeos/login/version_info_updater.cc

Index: chrome/browser/chromeos/login/version_info_updater.cc
diff --git a/chrome/browser/chromeos/login/version_info_updater.cc b/chrome/browser/chromeos/login/version_info_updater.cc
index 2c9ccc5b4160a140126e60164f4ce84f41a29e38..42aa2e4f58192405b9b46a0ffb4ae77e184284b3 100644
--- a/chrome/browser/chromeos/login/version_info_updater.cc
+++ b/chrome/browser/chromeos/login/version_info_updater.cc
@@ -59,10 +59,10 @@ void VersionInfoUpdater::StartUpdate(bool is_official_build) {
         base::Bind(&VersionInfoUpdater::OnVersion, base::Unretained(this)),
         &tracker_);
     boot_times_loader_.GetBootTimes(
-        &boot_times_consumer_,
-        base::Bind(is_official_build ? &VersionInfoUpdater::OnBootTimesNoop :
-                                       &VersionInfoUpdater::OnBootTimes,
-                   base::Unretained(this)));
+        base::Bind(is_official_build ? &VersionInfoUpdater::OnBootTimesNoop
+                                     : &VersionInfoUpdater::OnBootTimes,
+                   base::Unretained(this)),
+        &tracker_);
   } else {
     UpdateVersionLabel();
   }
@@ -195,11 +195,10 @@ void VersionInfoUpdater::OnVersion(const std::string& version) {
 }
 
 void VersionInfoUpdater::OnBootTimesNoop(
-    BootTimesLoader::Handle handle, BootTimesLoader::BootTimes boot_times) {
-}
+    const BootTimesLoader::BootTimes& boot_times) {}
 
 void VersionInfoUpdater::OnBootTimes(
-    BootTimesLoader::Handle handle, BootTimesLoader::BootTimes boot_times) {
+    const BootTimesLoader::BootTimes& boot_times) {
   const char* kBootTimesNoChromeExec =
       "Non-firmware boot took %.2f seconds (kernel %.2fs, system %.2fs)";
   const char* kBootTimesChromeExec =