Move MHTML file writing out of the renderer main thread.

third_party/WebKit/Source/web/WebFrameSerializer.cpp

 /*
  * Copyright (C) 2009 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 169 matching lines @@
            WebFrameSerializerCacheControlPolicy::FailForNoStoreMainFrame);
 
   if (!needToCheckNoStore)
     return true;
 
   return !cacheControlNoStoreHeaderPresent(*webLocalFrameImpl);
 }
 
 }  // namespace
 
-WebData WebFrameSerializer::generateMHTMLHeader(
+std::vector<char> WebFrameSerializer::generateMHTMLHeader(
     const WebString& boundary,
     WebLocalFrame* frame,
     MHTMLPartsGenerationDelegate* delegate) {
   TRACE_EVENT0("page-serialization", "WebFrameSerializer::generateMHTMLHeader");
   DCHECK(frame);
   DCHECK(delegate);
 
   if (!frameShouldBeSerializedAsMHTML(frame, delegate->cacheControlPolicy()))
-    return WebData();
+    return std::vector<char>();
 
   WebLocalFrameImpl* webLocalFrameImpl = toWebLocalFrameImpl(frame);
   DCHECK(webLocalFrameImpl);
 
   Document* document = webLocalFrameImpl->frame()->document();
 
-  RefPtr<SharedBuffer> buffer = SharedBuffer::create();
+  std::vector<char> output;
   MHTMLArchive::generateMHTMLHeader(boundary, document->title(),
-                                    document->suggestedMIMEType(), *buffer);
-  return buffer.release();
+                                    document->suggestedMIMEType(), output);
+  return output;
 }
 
-WebData WebFrameSerializer::generateMHTMLParts(
+std::vector<char> WebFrameSerializer::generateMHTMLParts(
     const WebString& boundary,
     WebLocalFrame* webFrame,
     MHTMLPartsGenerationDelegate* webDelegate) {
   TRACE_EVENT0("page-serialization", "WebFrameSerializer::generateMHTMLParts");
   DCHECK(webFrame);
   DCHECK(webDelegate);
 
   if (!frameShouldBeSerializedAsMHTML(webFrame,
                                       webDelegate->cacheControlPolicy()))
-    return WebData();
+    return std::vector<char>();
 
   // Translate arguments from public to internal blink APIs.
   LocalFrame* frame = toWebLocalFrameImpl(webFrame)->frame();
   MHTMLArchive::EncodingPolicy encodingPolicy =
       webDelegate->useBinaryEncoding()
           ? MHTMLArchive::EncodingPolicy::UseBinaryEncoding
           : MHTMLArchive::EncodingPolicy::UseDefaultEncoding;
 
   // Serialize.
   TRACE_EVENT_BEGIN0("page-serialization",
                      "WebFrameSerializer::generateMHTMLParts serializing");
   Vector<SerializedResource> resources;
   {
     SCOPED_BLINK_UMA_HISTOGRAM_TIMER(
         "PageSerialization.MhtmlGeneration.SerializationTime.SingleFrame");
     MHTMLFrameSerializerDelegate coreDelegate(*webDelegate);
     FrameSerializer serializer(resources, coreDelegate);
     serializer.serializeFrame(*frame);
   }
   TRACE_EVENT_END1("page-serialization",
                    "WebFrameSerializer::generateMHTMLParts serializing",
                    "resource count",
                    static_cast<unsigned long long>(resources.size()));
 
   // Get Content-ID for the frame being serialized.
   String frameContentID = webDelegate->getContentID(webFrame);
 
   // Encode serializer's output as MHTML.
-  RefPtr<SharedBuffer> output = SharedBuffer::create();
+  std::vector<char> output;
   {
     SCOPED_BLINK_UMA_HISTOGRAM_TIMER(
         "PageSerialization.MhtmlGeneration.EncodingTime.SingleFrame");
     bool isFirstResource = true;
     for (const SerializedResource& resource : resources) {
       TRACE_EVENT0("page-serialization",
                    "WebFrameSerializer::generateMHTMLParts encoding");
       // Frame is the 1st resource (see FrameSerializer::serializeFrame doc
       // comment). Frames get a Content-ID header.
       String contentID = isFirstResource ? frameContentID : String();
 
       MHTMLArchive::generateMHTMLPart(boundary, contentID, encodingPolicy,
-                                      resource, *output);
+                                      resource, output);
 
       isFirstResource = false;
     }
   }
-  return output.release();
+  return output;
 }
 
-WebData WebFrameSerializer::generateMHTMLFooter(const WebString& boundary) {
+std::vector<char> WebFrameSerializer::generateMHTMLFooter(
+    const WebString& boundary) {
   TRACE_EVENT0("page-serialization", "WebFrameSerializer::generateMHTMLFooter");
-  RefPtr<SharedBuffer> buffer = SharedBuffer::create();
-  MHTMLArchive::generateMHTMLFooter(boundary, *buffer);
-  return buffer.release();
+  std::vector<char> output;
+  MHTMLArchive::generateMHTMLFooter(boundary, output);
+  return output;
 }
 
 bool WebFrameSerializer::serialize(
     WebLocalFrame* frame,
     WebFrameSerializerClient* client,
     WebFrameSerializer::LinkRewritingDelegate* delegate) {
   WebFrameSerializerImpl serializerImpl(frame, client, delegate);
   return serializerImpl.serialize();
 }
 
@@ skipping 19 matching lines @@
     const WebString& baseTarget) {
   // TODO(yosin) We should call |FrameSerializer::baseTagDeclarationOf()|.
   if (baseTarget.isEmpty())
     return String("<base href=\".\">");
   String baseString = "<base href=\".\" target=\"" +
                       static_cast<const String&>(baseTarget) + "\">";
   return baseString;
 }
 
 }  // namespace blink