Use mojo for Chrome Loading, Part 1

net/http/http_response_headers.cc

Index: net/http/http_response_headers.cc
diff --git a/net/http/http_response_headers.cc b/net/http/http_response_headers.cc
index 9574b03bc851209f6d53797d7019690fcfd8d76b..8a5ed9834e0985e4b9cd3d8e361b0f94b3271018 100644
--- a/net/http/http_response_headers.cc
+++ b/net/http/http_response_headers.cc
@@ -168,9 +168,21 @@ HttpResponseHeaders::HttpResponseHeaders(base::PickleIterator* iter)
 void HttpResponseHeaders::Persist(base::Pickle* pickle,
                                   PersistOptions options) {
   if (options == PERSIST_RAW) {
+    // To avoid unnecessary copy, we don't call PersistTo here.
     pickle->WriteString(raw_headers_);
     return;  // Done.
   }
+  std::string blob;
+  PersistTo(options, &blob);
+  pickle->WriteString(blob);
+}
+
+void HttpResponseHeaders::PersistTo(PersistOptions options,
+                                    std::string* output) {
+  if (options == PERSIST_RAW) {
+    *output = raw_headers_;
+    return;  // Done.
+  }
 
   HeaderSet filter_headers;
 
@@ -193,13 +205,13 @@ void HttpResponseHeaders::Persist(base::Pickle* pickle,
   if ((options & PERSIST_SANS_SECURITY_STATE) == PERSIST_SANS_SECURITY_STATE)
     AddSecurityStateHeaders(&filter_headers);
 
-  std::string blob;
-  blob.reserve(raw_headers_.size());
+  output->clear();
+  output->reserve(raw_headers_.size());
 
   // This copies the status line w/ terminator null.
   // Note raw_headers_ has embedded nulls instead of \n,
   // so this just copies the first header line.
-  blob.assign(raw_headers_.c_str(), strlen(raw_headers_.c_str()) + 1);
+  output->assign(raw_headers_.c_str(), strlen(raw_headers_.c_str()) + 1);
 
   for (size_t i = 0; i < parsed_.size(); ++i) {
     DCHECK(!parsed_[i].is_continuation());
@@ -213,15 +225,13 @@ void HttpResponseHeaders::Persist(base::Pickle* pickle,
         base::StringPiece(parsed_[i].name_begin, parsed_[i].name_end));
     if (filter_headers.find(header_name) == filter_headers.end()) {
       // Make sure there is a null after the value.
-      blob.append(parsed_[i].name_begin, parsed_[k].value_end);
-      blob.push_back('\0');
+      output->append(parsed_[i].name_begin, parsed_[k].value_end);
+      output->push_back('\0');
     }
 
     i = k;
   }
-  blob.push_back('\0');
-
-  pickle->WriteString(blob);
+  output->push_back('\0');
 }
 
 void HttpResponseHeaders::Update(const HttpResponseHeaders& new_headers) {