Clear ResourceFetcher::m_validatedURLs if too many entries are added

Source/core/fetch/ResourceFetcher.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) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
     Copyright (C) 2009 Torch Mobile Inc. http://www.torchmobile.com/
 
     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
@@ skipping 676 matching lines @@
 
     if (type == ResourceLoadingFromCache && !resource->stillNeedsLoad() && !m_validatedURLs.contains(request.resourceRequest().url())) {
         // Resources loaded from memory cache should be reported the first time they're used.
         RefPtr<ResourceTimingInfo> info = ResourceTimingInfo::create(request.options().initiatorInfo.name, monotonicallyIncreasingTime());
         populateResourceTiming(info.get(), resource, true);
         m_scheduledResourceTimingReports.add(info, resource->type() == Resource::MainResource);
         if (!m_resourceTimingReportTimer.isActive())
             m_resourceTimingReportTimer.startOneShot(0, FROM_HERE);
     }
 
+    if (m_validatedURLs.size() >= 10000) {
+        m_validatedURLs.clear();

[kouhei (in TOK), 2014/11/14 08:37:51]

Can we have a ring buffer instead?

[hiroshige, 2014/11/14 09:02:05]

Done.

[kouhei (in TOK), 2014/11/14 09:15:57]

Sorry, I guess this is a better approach for now. I didn't notice
m_validatedURLs is a HashSet.

s/10000/kMaxValidatedURLsSize/ and add a comment that this is to prevent memory
bloat on m_validatedURLs.

[hiroshige, 2014/11/14 09:29:21]

Done in Patch Set 3.

+    }
     m_validatedURLs.add(request.resourceRequest().url());
 }
 
 ResourcePtr<Resource> ResourceFetcher::requestResource(Resource::Type type, FetchRequest& request)
 {
     ASSERT(request.options().synchronousPolicy == RequestAsynchronously || type == Resource::Raw);
 
     TRACE_EVENT0("blink", "ResourceFetcher::requestResource");
 
     KURL url = request.resourceRequest().url();
@@ skipping 858 matching lines @@
 
 void ResourceFetcher::trace(Visitor* visitor)
 {
     visitor->trace(m_document);
     visitor->trace(m_loaders);
     visitor->trace(m_multipartLoaders);
     ResourceLoaderHost::trace(visitor);
 }
 
 }