[Cleanup] Update histogram_tester.h includes in //storage

Update all histogram_tester.h includes in //storage to include
//base/test/metrics/histogram_tester.h

TBR=jsbell@chromium.org

Bug: 846421
Change-Id: I9148df884030530ce9684fe792f995cf93c5a4de
Reviewed-on: https://chromium-review.googlesource.com/1087208
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#564525}

storage/browser/quota/quota_manager_unittest.cc

@@ -21,7 +21,7 @@
 #include "base/run_loop.h"
 #include "base/stl_util.h"
 #include "base/sys_info.h"
-#include "base/test/histogram_tester.h"
+#include "base/test/metrics/histogram_tester.h"
 #include "base/test/scoped_task_environment.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"