Optimize writes upon ProfileManager::UpdateLastUser.

chrome/browser/profiles/profile_info_cache.cc

Index: chrome/browser/profiles/profile_info_cache.cc
diff --git a/chrome/browser/profiles/profile_info_cache.cc b/chrome/browser/profiles/profile_info_cache.cc
index 583441d71cb1544d2c15491af406807a7ec1385c..902b148c6c3005df0267727c8cef51e31d2e08fd 100644
--- a/chrome/browser/profiles/profile_info_cache.cc
+++ b/chrome/browser/profiles/profile_info_cache.cc
@@ -471,6 +471,11 @@ size_t ProfileInfoCache::GetAvatarIconIndexOfProfileAtIndex(size_t index)
 }
 
 void ProfileInfoCache::SetProfileActiveTimeAtIndex(size_t index) {
+  if (base::Time::Now() - GetProfileActiveTimeAtIndex(index) <
+      base::TimeDelta::FromHours(1)) {
+    return;
+  }
+
   scoped_ptr<base::DictionaryValue> info(
       GetInfoForProfileAtIndex(index)->DeepCopy());
   info->SetDouble(kActiveTimeKey, base::Time::Now().ToDoubleT());