Notification histograms should be thread-safe statics

third_party/WebKit/Source/modules/notifications/NotificationResourcesLoader.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 "modules/notifications/NotificationResourcesLoader.h"
 
 #include "platform/Histogram.h"
 #include "platform/weborigin/KURL.h"
 #include "public/platform/modules/notifications/WebNotificationConstants.h"
 #include "public/platform/modules/notifications/WebNotificationData.h"
 #include "public/platform/modules/notifications/WebNotificationResources.h"
 #include "skia/ext/image_operations.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "wtf/CurrentTime.h"
+#include "wtf/Threading.h"
 
 namespace blink {
 
 namespace {
 
 // Scales down |image| to fit within |maxSizePx| if its width or height is
 // larger than |maxSizePx| and returns the result. Otherwise does nothing and
 // returns |image| unchanged.
 // TODO(mvanouwerkerk): Explore doing the scaling on a background thread.
 SkBitmap scaleDownIfNeeded(const SkBitmap& image, int maxSizePx)
 {
     if (image.width() > maxSizePx || image.height() > maxSizePx) {
-        DEFINE_STATIC_LOCAL(CustomCountHistogram, scaleTimeHistogram, ("Notifications.Icon.ScaleDownTime", 1, 1000 * 10 /* 10 seconds max */, 50 /* buckets */));
+        DEFINE_THREAD_SAFE_STATIC_LOCAL(CustomCountHistogram, scaleTimeHistogram, new CustomCountHistogram("Notifications.Icon.ScaleDownTime", 1, 1000 * 10 /* 10 seconds max */, 50 /* buckets */));
         double startTime = monotonicallyIncreasingTimeMS();
         SkBitmap scaledImage = skia::ImageOperations::Resize(image, skia::ImageOperations::RESIZE_BEST, std::min(image.width(), maxSizePx), std::min(image.height(), maxSizePx));
         scaleTimeHistogram.count(monotonicallyIncreasingTimeMS() - startTime);
         return scaledImage;
     }
     return image;
 }
 
 } // namespace
 
@@ skipping 81 matching lines @@
     DCHECK_GT(m_pendingRequestCount, 0);
     m_pendingRequestCount--;
     if (!m_pendingRequestCount) {
         stop();
         (*m_completionCallback)(this);
         // The |this| pointer may have been deleted now.
     }
 }
 
 } // namespace blink