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

third_party/WebKit/Source/core/fetch/Resource.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, 2008, 2009, 2010, 2011 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
@@ skipping 841 matching lines @@
 
 void Resource::onMemoryStateChange(MemoryState state) {
   if (state != MemoryState::SUSPENDED)
     return;
   prune();
   if (!m_cacheHandler)
     return;
   m_cacheHandler->clearCachedMetadata(CachedMetadataHandler::CacheLocally);
 }
 
+bool Resource::isReloadable() const {
+  ResourceClientWalker<ResourceClient> w(m_finishedClients);
+  while (ResourceClient* c = w.next()) {
+    if (!c->isReloadable())
+      return false;
+  }
+  return true;
+}
+
 void Resource::onMemoryDump(WebMemoryDumpLevelOfDetail levelOfDetail,
                             WebProcessMemoryDump* memoryDump) const {
   static const size_t kMaxURLReportLength = 128;
   static const int kMaxResourceClientToShowInMemoryInfra = 10;
 
   const String dumpName = getMemoryDumpName();
   WebMemoryAllocatorDump* dump =
       memoryDump->createMemoryAllocatorDump(dumpName);
   dump->addScalar("encoded_size", "bytes", m_encodedSizeMemoryUsage);
   if (hasClientsOrObservers())
@@ skipping 236 matching lines @@
     case Resource::TextTrack:
     case Resource::Media:
     case Resource::Manifest:
       return false;
   }
   NOTREACHED();
   return false;
 }
 
 }  // namespace blink