Oilpan: Use weak pointers in StyleSheetContents caches.

Source/core/dom/StyleEngine.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 36 matching lines @@
 #include "core/page/InjectedStyleSheets.h"
 #include "core/page/Page.h"
 #include "core/frame/Settings.h"
 #include "core/svg/SVGStyleElement.h"
 #include "platform/URLPatternMatcher.h"
 
 namespace WebCore {
 
 using namespace HTMLNames;
 
-static HashMap<AtomicString, StyleSheetContents*>& textToSheetCache()
+static WillBeHeapHashMap<AtomicString, RawPtrWillBeWeakMember<StyleSheetContents> >& textToSheetCache()

[zerny-chromium, 2014/03/04 13:59:46]

Nit: use the typedef here too.

[Mads Ager (chromium), 2014/03/04 14:03:33]

The typedefs are local to the methods. And typedefs have proven to be a little
dangerous for us in the transition period because it is no longer completely
clear that there is something garbage collected going on. So I'd prefer not to.

 {
-    typedef HashMap<AtomicString, StyleSheetContents*> TextToSheetCache;
+    typedef WillBeHeapHashMap<AtomicString, RawPtrWillBeWeakMember<StyleSheetContents> > TextToSheetCache;
+#if ENABLE(OILPAN)
+    DEFINE_STATIC_LOCAL(Persistent<TextToSheetCache>, cache, (new TextToSheetCache));

[Erik Corry, 2014/03/04 14:09:27]

I think in another change we could use WillBePersistentHeapHashMap which avoids
the cache vs. *cache difference.

[Mads Ager (chromium), 2014/03/04 14:13:36]

Yeah, it would be nice if we could do that. Let's get this in and try to do that
for the 4 or 5 places where we use this pattern now.

+    return *cache;
+#else
     DEFINE_STATIC_LOCAL(TextToSheetCache, cache, ());
     return cache;
+#endif
 }
 
-static HashMap<StyleSheetContents*, AtomicString>& sheetToTextCache()
+static WillBeHeapHashMap<RawPtrWillBeWeakMember<StyleSheetContents>, AtomicString>& sheetToTextCache()

[zerny-chromium, 2014/03/04 13:59:46]

nit: ditto.

 {
-    typedef HashMap<StyleSheetContents*, AtomicString> SheetToTextCache;
+    typedef WillBeHeapHashMap<RawPtrWillBeWeakMember<StyleSheetContents>, AtomicString> SheetToTextCache;
+#if ENABLE(OILPAN)
+    DEFINE_STATIC_LOCAL(Persistent<SheetToTextCache>, cache, (new SheetToTextCache));
+    return *cache;
+#else
     DEFINE_STATIC_LOCAL(SheetToTextCache, cache, ());
     return cache;
+#endif
 }
 
 StyleEngine::StyleEngine(Document& document)
     : m_document(document)
     , m_isMaster(HTMLImport::isMaster(&document))
     , m_pendingStylesheets(0)
     , m_injectedStyleSheetCacheValid(false)
     , m_documentStyleSheetCollection(document)
     , m_documentScopeDirty(true)
     , m_usesSiblingRules(false)
@@ skipping 493 matching lines @@
 
 PassRefPtr<CSSStyleSheet> StyleEngine::createSheet(Element* e, const String& text, TextPosition startPosition, bool createdByParser)
 {
     RefPtr<CSSStyleSheet> styleSheet;
 
     e->document().styleEngine()->addPendingSheet();
 
     if (!e->document().inQuirksMode()) {
         AtomicString textContent(text);
 
-        HashMap<AtomicString, StyleSheetContents*>::AddResult result = textToSheetCache().add(textContent, 0);
+        WillBeHeapHashMap<AtomicString, RawPtrWillBeWeakMember<StyleSheetContents> >::AddResult result = textToSheetCache().add(textContent, nullptr);
         if (result.isNewEntry || !result.storedValue->value) {
             styleSheet = StyleEngine::parseSheet(e, text, startPosition, createdByParser);
             if (result.isNewEntry && styleSheet->contents()->maybeCacheable()) {
                 result.storedValue->value = styleSheet->contents();
                 sheetToTextCache().add(styleSheet->contents(), textContent);
             }
         } else {
             ASSERT(result.storedValue->value->maybeCacheable());
             styleSheet = CSSStyleSheet::createInline(result.storedValue->value, e, startPosition);
         }
@@ skipping 10 matching lines @@
 PassRefPtr<CSSStyleSheet> StyleEngine::parseSheet(Element* e, const String& text, TextPosition startPosition, bool createdByParser)
 {
     RefPtr<CSSStyleSheet> styleSheet;
     styleSheet = CSSStyleSheet::createInline(e, KURL(), startPosition, e->document().inputEncoding());
     styleSheet->contents()->parseStringAtPosition(text, startPosition, createdByParser);
     return styleSheet;
 }
 
 void StyleEngine::removeSheet(StyleSheetContents* contents)
 {
-    HashMap<StyleSheetContents*, AtomicString>::iterator it = sheetToTextCache().find(contents);
+    WillBeHeapHashMap<RawPtrWillBeWeakMember<StyleSheetContents>, AtomicString>::iterator it = sheetToTextCache().find(contents);
     if (it == sheetToTextCache().end())
         return;
 
     textToSheetCache().remove(it->value);
     sheetToTextCache().remove(contents);
 }
 
 }