Extract guts of ChromeStabilityMetricsProvider into helper class

components/metrics/system_memory_stats_recorder_linux.cc

 // 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.
 
-#include "chrome/browser/memory/system_memory_stats_recorder.h"
+#include "components/metrics/system_memory_stats_recorder.h"
 
 #include "base/metrics/histogram_macros.h"
 #include "base/process/process_metrics.h"
 
-namespace memory {
+namespace metrics {
 
 // Record a size in megabytes, a potential interval from 250MB up to 32 GB.
 #define UMA_HISTOGRAM_ALLOCATED_MEGABYTES(name, sample) \
   UMA_HISTOGRAM_CUSTOM_COUNTS(name, sample, 250, 32768, 50)
 
 // Records a statistics |sample| for UMA histogram |name|
 // using a linear distribution of buckets.
 #define UMA_HISTOGRAM_LINEAR(name, sample, max, buckets)                       \
   STATIC_HISTOGRAM_POINTER_BLOCK(                                              \
       name, Add(sample),                                                       \
@@ skipping 66 matching lines @@
 #endif
       UMA_HISTOGRAM_ALLOCATED_MEGABYTES(
           "Memory.OOMKill.Extensions.MemAllocatedMB", mem_allocated_mb);
       UMA_HISTOGRAM_LARGE_MEMORY_MB("Memory.OOMKill.Extensions.MemAvailableMB",
                                     mem_available_mb);
       break;
     }
   }
 }
 
-}  // namespace memory
+}  // namespace metrics