CSSStyleSheetResource should cache decoded text instead of raw bytes

third_party/WebKit/Source/core/fetch/CSSStyleSheetResource.h

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller <mueller@kde.org>
     Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
     Copyright (C) 2004, 2005, 2006, 2007, 2008 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.
@@ skipping 30 matching lines @@
 class CORE_EXPORT CSSStyleSheetResource final : public StyleSheetResource {
 public:
     enum class MIMETypeCheck { Strict, Lax };
 
     static CSSStyleSheetResource* fetch(FetchRequest&, ResourceFetcher*);
     static CSSStyleSheetResource* createForTest(const ResourceRequest&, const String& charset);
 
     ~CSSStyleSheetResource() override;
     DECLARE_VIRTUAL_TRACE();
 
-    const String sheetText(MIMETypeCheck = MIMETypeCheck::Strict) const;
+    const String sheetText(MIMETypeCheck = MIMETypeCheck::Strict);
 
     void didAddClient(ResourceClient*) override;
 
     StyleSheetContents* restoreParsedStyleSheet(const CSSParserContext&);
     void saveParsedStyleSheet(StyleSheetContents*);
 
     void appendData(const char* data, size_t length) override;
 
 private:
     class CSSStyleSheetResourceFactory : public ResourceFactory {
     public:
         CSSStyleSheetResourceFactory()
             : ResourceFactory(Resource::CSSStyleSheet) { }
 
         Resource* create(const ResourceRequest& request, const ResourceLoaderOptions& options, const String& charset) const override
         {
             return new CSSStyleSheetResource(request, options, charset);
         }
     };
     CSSStyleSheetResource(const ResourceRequest&, const ResourceLoaderOptions&, const String& charset);
 
-    bool canUseSheet(MIMETypeCheck) const;
     void checkNotify() override;
 
+    bool canUseSheet(MIMETypeCheck) const;
     void setParsedStyleSheetCache(StyleSheetContents*);
 
     void destroyDecodedDataIfPossible() override;
     void destroyDecodedDataForFailedRevalidation() override { destroyDecodedDataIfPossible(); }

[hiroshige, 2016/08/31 07:30:25]

We must clear |m_decodedSheetText| in destroyDecodedDataForFailedRevalidation().
Otherwise, the old stale |m_decodedSheetText| is used after revalidation (after
we receive response headers for revalidating request and before revalidating
loading is completed).
If bots are green, then it means we lack test cases...I'll create tests.

[kouhei (in TOK), 2016/08/31 10:27:43]

Done. Tests seems to be failing as expected.

 
     String m_decodedSheetText;
 
     Member<StyleSheetContents> m_parsedStyleSheetCache;
 
     bool m_didNotifyFirstData;
 };
 
 DEFINE_RESOURCE_TYPE_CASTS(CSSStyleSheet);
 
 } // namespace blink
 
 #endif