Get signals working in the EXTRA_DATA section of MHTML

content/browser/download/mhtml_extra_data_impl.h

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_BROWSER_DOWNLOAD_MHTML_EXTRA_DATA_IMPL_H_
+#define CONTENT_BROWSER_DOWNLOAD_MHTML_EXTRA_DATA_IMPL_H_
+
+#include "content/public/browser/mhtml_extra_data.h"
+
+namespace content {
+
+// Data fields used to build an additional MHTML part in the output file.
+struct MHTMLExtraDataPart {
+  std::string content_type;
+  std::string content_location;
+  std::string body;
+};
+
+// Class used as a data object for WebContents UserData to represent a MHTML
+// part that we plan to write into the output MHTML file.  Each MHTMLExtraPart
+// object in the contained vector lets us hold enough information to generate
+// one MHTML part.  Arbitrary extra MHTML parts to be added into the complete

[Dmitry Titov, 2017/03/29 18:53:06]

incomplete sentence...

[Pete Williamson, 2017/03/29 22:05:42]

Done.

+// file.  For instance, this might be used for gathering load time signals in
+// debug code for analysis.
+class MHTMLExtraDataImpl : public content::MHTMLExtraData {
+ public:
+  MHTMLExtraDataImpl();
+  ~MHTMLExtraDataImpl() override;
+
+  // Return the vector of parts to be disassembled.

[Dmitry Titov, 2017/03/29 18:53:06]

disassembled? 

[Pete Williamson, 2017/03/29 22:05:42]

Oops, serialized.  Fixed.

+  std::vector<MHTMLExtraDataPart>& parts() { return parts_; }
+  const std::vector<MHTMLExtraDataPart>& parts() const { return parts_; }
+
+  void AddExtraMHTMLPart(const std::string& content_type,

[Dmitry Titov, 2017/03/29 18:53:06]

This shoudl have a comment saying it's implementation of MHTMLExtraData.

[Pete Williamson, 2017/03/29 22:05:42]

I don't think I understood your suggestion, but I did add a comment, please
check to see if that is what you wanted.

+                         const std::string& content_location,
+                         const std::string& body) override;
+
+ private:
+  std::vector<MHTMLExtraDataPart> parts_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_DOWNLOAD_MHTML_EXTRA_DATA_IMPL_H_