[wrapper-tracing] Untangle non-trivial mixin ctors

third_party/WebKit/Source/modules/fetch/FetchRequestData.cpp

Index: third_party/WebKit/Source/modules/fetch/FetchRequestData.cpp
diff --git a/third_party/WebKit/Source/modules/fetch/FetchRequestData.cpp b/third_party/WebKit/Source/modules/fetch/FetchRequestData.cpp
index 1385942196b322e75c6187f512492209468af444..05d43ff007b030d9098a28c7231da4d1e6fff2a6 100644
--- a/third_party/WebKit/Source/modules/fetch/FetchRequestData.cpp
+++ b/third_party/WebKit/Source/modules/fetch/FetchRequestData.cpp
@@ -34,7 +34,7 @@ FetchRequestData* FetchRequestData::create(
        it != webRequest.headers().end(); ++it)
     request->m_headerList->append(it->key, it->value);
   if (webRequest.blobDataHandle())
-    request->setBuffer(new BodyStreamBuffer(
+    request->setBuffer(BodyStreamBuffer::create(
         scriptState, new BlobBytesConsumer(scriptState->getExecutionContext(),
                                            webRequest.blobDataHandle())));
   request->setContext(webRequest.requestContext());
@@ -84,7 +84,8 @@ FetchRequestData* FetchRequestData::pass(ScriptState* scriptState) {
   FetchRequestData* request = FetchRequestData::cloneExceptBody();
   if (m_buffer) {
     request->m_buffer = m_buffer;
-    m_buffer = new BodyStreamBuffer(scriptState, BytesConsumer::createClosed());
+    m_buffer =
+        BodyStreamBuffer::create(scriptState, BytesConsumer::createClosed());
     m_buffer->closeAndLockAndDisturb();
   }
   return request;