Allow safe per-thread heap compaction UMA reporting.

third_party/WebKit/Source/platform/heap/HeapCompact.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 "platform/heap/HeapCompact.h"
 
 #include "platform/Histogram.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/heap/Heap.h"
 #include "platform/heap/SparseHeapBitmap.h"
@@ skipping 410 matching lines @@
     return;
 
 #if DEBUG_HEAP_COMPACTION
   if (m_fixups)
     m_fixups->dumpDebugStats();
 #endif
   m_fixups.reset();
   m_doCompact = false;
 
   double timeForHeapCompaction = WTF::currentTimeMS() - m_startCompactionTimeMS;
-  DEFINE_STATIC_LOCAL(CustomCountHistogram, timeForHeapCompactionHistogram,
-                      ("BlinkGC.TimeForHeapCompaction", 1, 10 * 1000, 50));
+  DEFINE_THREAD_SAFE_STATIC_LOCAL(
+      CustomCountHistogram, timeForHeapCompactionHistogram,
+      new CustomCountHistogram("BlinkGC.TimeForHeapCompaction", 1, 10 * 1000,
+                               50));
   timeForHeapCompactionHistogram.count(timeForHeapCompaction);
   m_startCompactionTimeMS = 0;
 
-  DEFINE_STATIC_LOCAL(
+  DEFINE_THREAD_SAFE_STATIC_LOCAL(
       CustomCountHistogram, objectSizeFreedByHeapCompaction,
-      ("BlinkGC.ObjectSizeFreedByHeapCompaction", 1, 4 * 1024 * 1024, 50));
+      new CustomCountHistogram("BlinkGC.ObjectSizeFreedByHeapCompaction", 1,
+                               4 * 1024 * 1024, 50));
   objectSizeFreedByHeapCompaction.count(m_freedSize / 1024);
 
 #if DEBUG_LOG_HEAP_COMPACTION_RUNNING_TIME
   LOG_HEAP_COMPACTION_INTERNAL(
       "Compaction stats: time=%gms, pages freed=%zu, size=%zu\n",
       timeForHeapCompaction, m_freedPages, m_freedSize);
 #else
   LOG_HEAP_COMPACTION("Compaction stats: freed pages=%zu size=%zu\n",
                       m_freedPages, m_freedSize);
 #endif
 }
 
 void HeapCompact::addCompactingPage(BasePage* page) {
   DCHECK(m_doCompact);
   DCHECK(isCompactingArena(page->arena()->arenaIndex()));
   fixups().addCompactingPage(page);
 }
 
 bool HeapCompact::scheduleCompactionGCForTesting(bool value) {
   bool current = s_forceCompactionGC;
   s_forceCompactionGC = value;
   return current;
 }
 
 }  // namespace blink