Do not call MemoryCache::prune() when a client/observer is removed

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
     License as published by the Free Software Foundation; either
@@ skipping 711 matching lines @@
 {
     if (!hasClientsOrObservers() && m_isAlive) {
         m_isAlive = false;
         memoryCache()->makeDead(this);
         allClientsAndObserversRemoved();
 
         // RFC2616 14.9.2:
         // "no-store: ... MUST make a best-effort attempt to remove the information from volatile storage as promptly as possible"
         // "... History buffers MAY store such responses as part of their normal operation."
         // We allow non-secure content to be reused in history, but we do not allow secure content to be reused.
-        if (hasCacheControlNoStoreHeader() && url().protocolIs("https")) {
+        if (hasCacheControlNoStoreHeader() && url().protocolIs("https"))
             memoryCache()->remove(this);

[yhirano, 2016/09/15 08:30:43]

Hm, is this statement still needed?

[hiroshige, 2016/09/15 08:45:33]

I'm not sure.
I created a CL https://codereview.chromium.org/2346483005 and seeing whether
this is covered by tests.

(Anyway it should be handled in a separate CL because it affects caching
correctness, and MemoryCache::remove() is not harmful when executed in
prefinalizers)

-            memoryCache()->prune();
-        } else {
-            memoryCache()->prune(this);

[Nate Chapin, 2016/09/16 21:28:47]

I think this is the only callsite that passes a non-null Resource* to prune().
Could we remove that unused logic, too?

[hiroshige, 2016/09/29 06:27:17]

Done.

-        }
     }
-    // This object may be dead here.
 }
 
 void Resource::allClientsAndObserversRemoved()
 {
     if (!m_loader)
         return;
     if (m_type == Raw)
         cancelTimerFired(&m_cancelTimer);
     else if (!m_cancelTimer.isActive())
         m_cancelTimer.startOneShot(0, BLINK_FROM_HERE);
@@ skipping 315 matching lines @@
     case Resource::TextTrack:
     case Resource::Media:
     case Resource::Manifest:
         return false;
     }
     NOTREACHED();
     return false;
 }
 
 } // namespace blink