Move MHTML file writing out of the renderer main thread.

third_party/WebKit/Source/platform/mhtml/MHTMLArchive.h

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 17 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef MHTMLArchive_h
 #define MHTMLArchive_h
 
 #include "platform/heap/Handle.h"
 #include "wtf/HashMap.h"
 #include "wtf/Vector.h"
 #include "wtf/text/StringHash.h"
+#include <vector>
 
 namespace blink {
 
 class ArchiveResource;
 class KURL;
 class SharedBuffer;
 
 struct SerializedResource;
 
 class PLATFORM_EXPORT MHTMLArchive final : public GarbageCollected<MHTMLArchive> {
 public:
     static MHTMLArchive* create(const KURL&, PassRefPtr<const SharedBuffer>);
 
     // Binary encoding results in smaller MHTML files but they might not work in other browsers.
     enum EncodingPolicy {
         UseDefaultEncoding,
         UseBinaryEncoding
     };
 
     // Generates an MHTML header and appends it to |outputBuffer|.
     //
     // Same |boundary| needs to used for all generateMHTMLHeader and
     // generateMHTMLPart and generateMHTMLFooter calls that belong to the same
     // MHTML document (see also rfc1341, section 7.2.1, "boundary" description).
     static void generateMHTMLHeader(
         const String& boundary, const String& title, const String& mimeType,
-        SharedBuffer& outputBuffer);
+        std::vector<char>& outputBuffer);

[carlosk, 2016/10/03 23:51:05]

Is it really OK to pass non const references in Blink? Or should I change this
to a pointer instead?

[carlosk, 2016/10/04 21:49:53]

Just for the record: I did ask dcheng@ directly about this and passing non-const
references is acceptable in Blink as it implies a safe, never null "pointer" to
an output argument.

 
     // Serializes SerializedResource as an MHTML part and appends it in
     // |outputBuffer|.
     //
     // Same |boundary| needs to used for all generateMHTMLHeader and
     // generateMHTMLPart and generateMHTMLFooter calls that belong to the same
     // MHTML document (see also rfc1341, section 7.2.1, "boundary" description).
     //
     // If |contentID| is non-empty, then it will be used as a Content-ID header.
     // See rfc2557 - section 8.3 - "Use of the Content-ID header and CID URLs".
     static void generateMHTMLPart(
         const String& boundary, const String& contentID,
         EncodingPolicy, const SerializedResource&,
-        SharedBuffer& outputBuffer);
+        std::vector<char>& outputBuffer);
 
     // Generates an MHTML footer and appends it to |outputBuffer|.
     //
     // Same |boundary| needs to used for all generateMHTMLHeader and
     // generateMHTMLPart and generateMHTMLFooter calls that belong to the same
     // MHTML document (see also rfc1341, section 7.2.1, "boundary" description).
     static void generateMHTMLFooter(
         const String& boundary,
-        SharedBuffer& outputBuffer);
+        std::vector<char>& outputBuffer);
 
     typedef HeapHashMap<String, Member<ArchiveResource>> SubArchiveResources;
 
     ArchiveResource* mainResource() { return m_mainResource.get(); }
     ArchiveResource* subresourceForURL(const KURL&) const;
 
     DECLARE_TRACE();
 
 private:
     MHTMLArchive();
 
     void setMainResource(ArchiveResource*);
     void addSubresource(ArchiveResource*);
     static bool canLoadArchive(const KURL&);
 
     Member<ArchiveResource> m_mainResource;
     SubArchiveResources m_subresources;
 };
 
 } // namespace blink
 
 #endif