Removed RefPtr::Release.

third_party/WebKit/Source/core/exported/WebFrameSerializer.cpp

Index: third_party/WebKit/Source/core/exported/WebFrameSerializer.cpp
diff --git a/third_party/WebKit/Source/core/exported/WebFrameSerializer.cpp b/third_party/WebKit/Source/core/exported/WebFrameSerializer.cpp
index 8bcba88de5a9ec19ff57336c14e76fefb7b2a93c..efe480cbc8d6f765b325698f32c71e9488e52335 100644
--- a/third_party/WebKit/Source/core/exported/WebFrameSerializer.cpp
+++ b/third_party/WebKit/Source/core/exported/WebFrameSerializer.cpp
@@ -453,7 +453,7 @@ WebThreadSafeData WebFrameSerializer::GenerateMHTMLHeader(
   MHTMLArchive::GenerateMHTMLHeader(boundary, document->title(),
                                     document->SuggestedMIMEType(),
                                     *buffer->MutableData());
-  return buffer.Release();
+  return buffer;
 }
 
 WebThreadSafeData WebFrameSerializer::GenerateMHTMLParts(
@@ -516,7 +516,7 @@ WebThreadSafeData WebFrameSerializer::GenerateMHTMLParts(
                                       *output->MutableData());
     }
   }
-  return output.Release();
+  return output;
 }
 
 bool WebFrameSerializer::Serialize(