Make time_to_first_suspension's default 1800sec

chrome/browser/memory/tab_manager.cc

Index: chrome/browser/memory/tab_manager.cc
diff --git a/chrome/browser/memory/tab_manager.cc b/chrome/browser/memory/tab_manager.cc
index 56aae1cde41797cce72fee5f6f612945155a9911..cfc57fa94fd1cf4d64af5d7540d3caf6c5ac8446 100644
--- a/chrome/browser/memory/tab_manager.cc
+++ b/chrome/browser/memory/tab_manager.cc
@@ -230,7 +230,7 @@ void TabManager::Start() {
   if (purge_and_suspend_time.empty() ||
       !base::StringToUint(purge_and_suspend_time,
                           &time_to_first_suspension_sec))
-    time_to_first_suspension_sec = 108000;
+    time_to_first_suspension_sec = kDefaultTimeToFirstPurgeInSeconds;
   time_to_first_suspension_ =
       base::TimeDelta::FromSeconds(time_to_first_suspension_sec);
 }