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 161 matching lines @@
         || (!frame->parent() && cacheControlPolicy == 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::move(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();
+        boundary, document->title(), document->suggestedMIMEType(), output);
+    return std::move(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::move(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);
+                boundary, contentID, encodingPolicy, resource, output);
 
             isFirstResource = false;
         }
     }
-    return output.release();
+    return std::move(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 std::move(output);
 }
 
 bool WebFrameSerializer::serialize(
     WebLocalFrame* frame,
     WebFrameSerializerClient* client,
     WebFrameSerializer::LinkRewritingDelegate* delegate)
 {
     WebFrameSerializerImpl serializerImpl(frame, client, delegate);
     return serializerImpl.serialize();
 }
@@ skipping 17 matching lines @@
 WebString WebFrameSerializer::generateBaseTagDeclaration(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