Remove unnecessary array allocation in cronet_bidirectional_stream_adapter.cc

Save arguments passed in through WritevData directly instead
of a list of IOBufferWithByteBuffer.

This saves unnecessary array allocations to reconstruct Java
arguments for invoking onWriteCompleted.

BUG=611056

Review-Url: https://codereview.chromium.org/1969893002
Cr-Commit-Position: refs/heads/master@{#393901}
diff --git a/net/quic/quic_chromium_client_stream.cc b/net/quic/quic_chromium_client_stream.cc
index 1aa8e53..0f21d51 100644
--- a/net/quic/quic_chromium_client_stream.cc
+++ b/net/quic/quic_chromium_client_stream.cc
@@ -140,7 +140,7 @@
 }
 
 int QuicChromiumClientStream::WritevStreamData(
-    const std::vector<IOBuffer*>& buffers,
+    const std::vector<scoped_refptr<IOBuffer>>& buffers,
     const std::vector<int>& lengths,
     bool fin,
     const CompletionCallback& callback) {