[Tentaive patch for discussion] Add Purge+Suspend metrics as UMA.

third_party/WebKit/Source/web/WebMemoryStatistics.cpp

+// Copyright 2016 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 "public/web/WebMemoryStatistics.h"
+
+#include "platform/heap/Heap.h"
+#include "wtf/allocator/Partitions.h"
+
+namespace blink {
+
+namespace {
+
+    class LightPartitionStatsDumperImpl : public WTF::PartitionStatsDumper {
+    public:
+        LightPartitionStatsDumperImpl()
+            : m_totalActiveBytes(0)
+            , m_totalResidentBytes(0)
+        {
+        }
+
+        void partitionDumpTotals(const char* partitionName, const WTF::PartitionMemoryStats*) override;
+        void partitionsDumpBucketStats(const char* partitionName, const WTF::PartitionBucketMemoryStats*) override {}
+
+        size_t totalActiveBytes() const { return m_totalActiveBytes; }
+        size_t totalResidentBytes() const { return m_totalResidentBytes; }
+
+    private:
+        size_t m_totalActiveBytes;
+        size_t m_totalResidentBytes;
+    };
+
+    void LightPartitionStatsDumperImpl::partitionDumpTotals(const char* partitionName, const WTF::PartitionMemoryStats* memoryStats)
+    {
+        m_totalActiveBytes += memoryStats->totalActiveBytes;
+        m_totalResidentBytes += memoryStats->totalResidentBytes;
+    }
+}
+
+WebMemoryStatistics WebMemoryStatistics::Get()
+{
+    LightPartitionStatsDumperImpl dumper;
+    WebMemoryStatistics statistics;
+
+    WTF::Partitions::dumpMemoryStats(true, &dumper);
+    statistics.partitionAllocTotalAllocatedBytes = dumper.totalActiveBytes();
+    statistics.partitionAllocTotalBytes = dumper.totalResidentBytes();
+
+    statistics.blinkGCTotalBytes = ProcessHeap::totalAllocatedSpace();
+    statistics.blinkGCTotalAllocatedBytes = ProcessHeap::totalAllocatedObjectSize() + ProcessHeap::totalMarkedObjectSize();
+    return statistics;
+}
+}