Get signals working in the EXTRA_DATA section of MHTML

content/browser/download/mhtml_extra_parts_impl.cc

+// 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.
+
+#include "content/browser/download/mhtml_extra_parts_impl.h"
+
+namespace {
+// Only the address of this variable is used.  It is used as a key to UserData.
+const int kMHTMLExtraPartsKey = 0;
+}
+
+namespace content {
+
+MHTMLExtraPartsImpl::MHTMLExtraPartsImpl() = default;
+
+MHTMLExtraPartsImpl::~MHTMLExtraPartsImpl() = default;
+
+MHTMLExtraParts* MHTMLExtraParts::FromWebContents(WebContents* contents) {
+  // Get the MHTMLExtraPartsImpl from the web contents.
+  MHTMLExtraPartsImpl* extra_data_impl = static_cast<MHTMLExtraPartsImpl*>(
+      contents->GetUserData(&kMHTMLExtraPartsKey));
+
+  // If we did not have one on the web contents already, make one and put it on
+  // the web contents.
+  if (extra_data_impl == nullptr) {
+    extra_data_impl = new MHTMLExtraPartsImpl();
+    contents->SetUserData(&kMHTMLExtraPartsKey,
+                          std::unique_ptr<MHTMLExtraParts>(
+                              static_cast<MHTMLExtraParts*>(extra_data_impl)));
+  }
+  return static_cast<MHTMLExtraParts*>(extra_data_impl);
+}
+
+int64_t MHTMLExtraPartsImpl::size() {
+  return parts_.size();
+}
+
+void MHTMLExtraPartsImpl::AddExtraMHTMLPart(const std::string& content_type,
+                                            const std::string& content_location,
+                                            const std::string& body) {
+  MHTMLExtraDataPart part;
+  part.content_type = content_type;
+  part.content_location = content_location;
+  part.body = body;
+
+  // Add this part to the list of parts to be saved out when the file is
+  // written.
+  parts_.push_back(part);
+}
+
+}  // namespace content