net: Make UploadDataStream::Init() asynchronous.

net/base/upload_file_element_reader.h

Index: net/base/upload_file_element_reader.h
diff --git a/net/base/upload_file_element_reader.h b/net/base/upload_file_element_reader.h
index 34d8194cd68d7878baf26efdfab557c21aaef25d..cc8e83053a2979161ed6ad7931e0e4846b814a08 100644
--- a/net/base/upload_file_element_reader.h
+++ b/net/base/upload_file_element_reader.h
@@ -9,6 +9,7 @@
 #include "base/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
 #include "base/time.h"
 #include "net/base/upload_element_reader.h"
 
@@ -26,12 +27,19 @@ class NET_EXPORT_PRIVATE UploadFileElementReader : public UploadElementReader {
   virtual ~UploadFileElementReader();
 
   // UploadElementReader overrides:
+  virtual int Init(const CompletionCallback& callback) OVERRIDE;
   virtual int InitSync() OVERRIDE;
   virtual uint64 GetContentLength() const OVERRIDE;
   virtual uint64 BytesRemaining() const OVERRIDE;
   virtual int ReadSync(char* buf, int buf_length) OVERRIDE;
 
  private:
+  // This method is used to implement Init().
+  void OnInitCompleted(scoped_ptr<FileStream>* file_stream,
+                       uint64* content_length,
+                       int* result,
+                       const CompletionCallback& callback);
+
   // Sets an value to override the result for GetContentLength().
   // Used for tests.
   struct NET_EXPORT_PRIVATE ScopedOverridingContentLengthForTests {
@@ -46,6 +54,7 @@ class NET_EXPORT_PRIVATE UploadFileElementReader : public UploadElementReader {
   scoped_ptr<FileStream> file_stream_;
   uint64 content_length_;
   uint64 bytes_remaining_;
+  base::WeakPtrFactory<UploadFileElementReader> weak_ptr_factory_;
 
   FRIEND_TEST_ALL_PREFIXES(UploadDataStreamTest, FileSmallerThanLength);
   FRIEND_TEST_ALL_PREFIXES(HttpNetworkTransactionTest,