Extract guts of ChromeStabilityMetricsProvider into helper class

chrome/browser/memory/system_memory_stats_recorder.h

Index: chrome/browser/memory/system_memory_stats_recorder.h
diff --git a/chrome/browser/memory/system_memory_stats_recorder.h b/chrome/browser/memory/system_memory_stats_recorder.h
deleted file mode 100644
index 5dc354067575c0779b5be6737eb5ec78ddf8daad..0000000000000000000000000000000000000000
--- a/chrome/browser/memory/system_memory_stats_recorder.h
+++ /dev/null
@@ -1,30 +0,0 @@
-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef CHROME_BROWSER_MEMORY_SYSTEM_MEMORY_STATS_RECORDER_H_
-#define CHROME_BROWSER_MEMORY_SYSTEM_MEMORY_STATS_RECORDER_H_
-
-namespace memory {
-
-// Record a memory size in megabytes, over a potential interval up to 32 GB.
-#define UMA_HISTOGRAM_LARGE_MEMORY_MB(name, sample) \
-  UMA_HISTOGRAM_CUSTOM_COUNTS(name, sample, 1, 32768, 50)
-
-// The type of memory UMA stats to be recorded in RecordMemoryStats.
-enum RecordMemoryStatsType {
-  // When a tab was discarded.
-  RECORD_MEMORY_STATS_TAB_DISCARDED,
-
-  // Right after the renderer for contents was killed.
-  RECORD_MEMORY_STATS_CONTENTS_OOM_KILLED,
-
-  // Right after the renderer for extensions was killed.
-  RECORD_MEMORY_STATS_EXTENSIONS_OOM_KILLED,
-};
-
-void RecordMemoryStats(RecordMemoryStatsType type);
-
-}  // namespace memory
-
-#endif  // CHROME_BROWSER_MEMORY_SYSTEM_MEMORY_STATS_RECORDER_H_