New cache for the activity tracker.

base/debug/activity_tracker_unittest.cc

Index: base/debug/activity_tracker_unittest.cc
diff --git a/base/debug/activity_tracker_unittest.cc b/base/debug/activity_tracker_unittest.cc
index c36d8fac352cb169759d9a9e07db5c9648860010..544c20e6b1322d7a2d7edf3b2eb43ad0825bd4e5 100644
--- a/base/debug/activity_tracker_unittest.cc
+++ b/base/debug/activity_tracker_unittest.cc
@@ -13,9 +13,11 @@
 #include "base/files/scoped_temp_dir.h"
 #include "base/memory/ptr_util.h"
 #include "base/pending_task.h"
+#include "base/rand_util.h"
 #include "base/synchronization/condition_variable.h"
 #include "base/synchronization/lock.h"
 #include "base/synchronization/spin_wait.h"
+#include "base/threading/platform_thread.h"
 #include "base/threading/simple_thread.h"
 #include "base/time/time.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -72,8 +74,7 @@ class ActivityTrackerTest : public testing::Test {
     GlobalActivityTracker* global_tracker = GlobalActivityTracker::Get();
     if (!global_tracker)
       return 0;
-    return global_tracker->available_memories_count_.load(
-        std::memory_order_relaxed);
+    return global_tracker->available_memories_.used();
   }
 
   static void DoNothing() {}