Add metrics for how often APNGs are used

third_party/WebKit/Source/platform/image-decoders/png/PNGImageReader.cpp

 /*
  * Copyright (C) 2006 Apple Computer, Inc.
  * Copyright (C) Research In Motion Limited 2009-2010. All rights reserved.
  *
  * Portions are Copyright (C) 2001 mozilla.org
  *
  * Other contributors:
  *   Stuart Parmenter <stuart@mozilla.com>
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 21 matching lines @@
  * version of this file under the LGPL, indicate your decision by
  * deletingthe provisions above and replace them with the notice and
  * other provisions required by the MPL or the GPL, as the case may be.
  * If you do not delete the provisions above, a recipient may use your
  * version of this file under any of the LGPL, the MPL or the GPL.
  */
 
 #include "platform/image-decoders/png/PNGImageReader.h"
 
 #include <memory>
+#include "platform/Histogram.h"
 #include "platform/image-decoders/FastSharedBufferReader.h"
 #include "platform/image-decoders/SegmentReader.h"
 #include "platform/image-decoders/png/PNGImageDecoder.h"
 #include "wtf/PtrUtil.h"
 #include "zlib.h"
 
 namespace {
 
 inline blink::PNGImageDecoder* imageDecoder(png_structp png) {
   return static_cast<blink::PNGImageDecoder*>(png_get_progressive_ptr(png));
@@ skipping 476 matching lines @@
 
     if (isChunk(chunk, "IDAT")) {
       // Done with header chunks.
       m_idatOffset = m_readOffset;
       m_fctlNeedsDatChunk = false;
       if (m_ignoreAnimation)
         m_isAnimated = false;
       if (!m_isAnimated || 1 == m_reportedFrameCount)
         m_decoder->setRepetitionCount(cAnimationNone);
       m_decoder->headerAvailable();
+      {
+        DEFINE_THREAD_SAFE_STATIC_LOCAL(
+            BooleanHistogram, apngHistogram,
+            new BooleanHistogram("Blink.DecodedImage.APNG"));
+        apngHistogram.count(m_isAnimated);
+      }
       return true;
     }
 
     // Wait until the entire chunk is available for parsing simplicity.
     if (reader.size() < m_readOffset + length + 12)
       break;
 
     if (isChunk(chunk, "acTL")) {
       if (m_ignoreAnimation)
         continue;
@@ skipping 125 matching lines @@
       break;
     default:
       return false;
   }
 
   m_fctlNeedsDatChunk = true;
   return true;
 }
 
 }  // namespace blink