net: Don't merge HTTP headers and body if the body is not in memory.

net/base/upload_data_stream.h

Index: net/base/upload_data_stream.h
diff --git a/net/base/upload_data_stream.h b/net/base/upload_data_stream.h
index a30850ab655b0d83f4f79b1094c32ac129c86259..e71cc686ec6b1dbcb37feea16487051a46127eb0 100644
--- a/net/base/upload_data_stream.h
+++ b/net/base/upload_data_stream.h
@@ -66,6 +66,9 @@ class NET_EXPORT UploadDataStream {
   // returns true only after the data in buf() has been consumed.
   bool IsOnLastChunk() const;
 
+  // Returns true if the upload data in the stream is entirely in memory.
+  bool IsInMemory() const;
+
   // This method is provided only to be used by unit tests.
   static void set_merge_chunks(bool merge) { merge_chunks_ = merge; }