[TabManager] Enable tab discarding by default.

chrome/browser/memory/tab_manager_unittest.cc

Index: chrome/browser/memory/tab_manager_unittest.cc
diff --git a/chrome/browser/memory/tab_manager_unittest.cc b/chrome/browser/memory/tab_manager_unittest.cc
index 207aac9e07b4834642e7b97e29b6195389f16792..8036a405650f9aabda3a979a7f21bf3efa482678 100644
--- a/chrome/browser/memory/tab_manager_unittest.cc
+++ b/chrome/browser/memory/tab_manager_unittest.cc
@@ -449,7 +449,7 @@ TEST_F(TabManagerTest, DiscardedTabKeepsLastActiveTime) {
 
 // Test to see if a tab can only be discarded once. On Windows and Mac, this
 // defaults to true unless overridden through a variation parameter. On other
-// platforms, it's always false
+// platforms, it's always false.
 #if defined(OS_WIN) || defined(OS_MACOSX)
 TEST_F(TabManagerTest, CanOnlyDiscardOnce) {
   TabManager tab_manager;