Add UMA to estimate deroppable memory usage of encoded data size in Resources

third_party/WebKit/Source/core/fetch/ImageResource.cpp

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
     Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
     Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
     Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
     version 2 of the License, or (at your option) any later version.
 
     This library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Library General Public License for more details.
 
     You should have received a copy of the GNU Library General Public License
     along with this library; see the file COPYING.LIB.  If not, write to
     the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.
 */
 
 #include "core/fetch/ImageResource.h"
 
+#include "base/metrics/histogram_macros.h"
 #include "core/fetch/ImageResourceObserver.h"
 #include "core/fetch/MemoryCache.h"
 #include "core/fetch/ResourceClient.h"
 #include "core/fetch/ResourceFetcher.h"
 #include "core/fetch/ResourceLoader.h"
 #include "core/fetch/ResourceLoadingLog.h"
 #include "core/svg/graphics/SVGImage.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/SharedBuffer.h"
 #include "platform/geometry/IntSize.h"
@@ skipping 209 matching lines @@
 void ImageResource::destroyDecodedDataForFailedRevalidation() {
   clearImage();
   setDecodedSize(0);
 }
 
 void ImageResource::destroyDecodedDataIfPossible() {
   if (!m_image)
     return;
   CHECK(!errorOccurred());
   m_image->destroyDecodedData();
+  if (!isPreloaded() && isReloadable()) {
+    UMA_HISTOGRAM_MEMORY_KB("Memory.Renderer.EstimantedDroppableEncodedSize",
+                            encodedSize() / 1024);
+  }
 }
 
 void ImageResource::doResetAnimation() {
   if (m_image)
     m_image->resetAnimation();
 }
 
 void ImageResource::allClientsAndObserversRemoved() {
   if (m_image) {
     CHECK(!errorOccurred());
@@ skipping 414 matching lines @@
            WebServiceWorkerResponseTypeOpaque;
   }
   if (!getImage()->currentFrameHasSingleSecurityOrigin())
     return false;
   if (passesAccessControlCheck(securityOrigin))
     return true;
   return !securityOrigin->taintsCanvas(response().url());
 }
 
 }  // namespace blink