net: Reset UploadDataStream on HttpNetworkTransaction destruction

Make UploadDataStream::Reset public.
Call Reset() from HttpNetworkTransaction's dtor.
Add tests.

BUG=244725
TEST=net_unittests --gtest_filter="*HttpNetworkTransactionTest.CancelDuringInitRequestBody*"

Review URL: https://codereview.chromium.org/25217002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226433 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/net/base/upload_data_stream.h b/net/base/upload_data_stream.h
index 8220315b..ac14e38 100644
--- a/net/base/upload_data_stream.h
+++ b/net/base/upload_data_stream.h
@@ -94,10 +94,10 @@
   // Adds the given chunk of bytes to be sent with chunked transfer encoding.
   void AppendChunk(const char* bytes, int bytes_len, bool is_last_chunk);
 
- private:
   // Resets this instance to the uninitialized state.
   void Reset();
 
+ private:
   // Runs Init() for all element readers.
   // This method is used to implement Init().
   int InitInternal(int start_index, const CompletionCallback& callback);