Add a minimal AttachmentUploaderImpl.

sync/internal_api/public/attachments/attachment_server_url_builder.h

Index: sync/internal_api/public/attachments/attachment_server_url_builder.h
diff --git a/sync/internal_api/public/attachments/attachment_server_url_builder.h b/sync/internal_api/public/attachments/attachment_server_url_builder.h
new file mode 100644
index 0000000000000000000000000000000000000000..543d41ee562355c13ad1288be214c271426a2936
--- /dev/null
+++ b/sync/internal_api/public/attachments/attachment_server_url_builder.h
@@ -0,0 +1,44 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SYNC_INTERNAL_API_PUBLIC_ATTACHMENTS_ATTACHMENT_SERVER_URL_BUILDER_H_
+#define SYNC_INTERNAL_API_PUBLIC_ATTACHMENTS_ATTACHMENT_SERVER_URL_BUILDER_H_
+
+#include <string>
+
+#include "sync/api/attachments/attachment_id.h"
+#include "sync/base/sync_export.h"
+#include "url/gurl.h"
+
+namespace syncer {
+
+// Used to obtain the upload URL for an attachment.
+class SYNC_EXPORT AttachmentServerURLBuilder {
+ public:
+  enum Scheme {
+    SCHEME_HTTPS,
+    SCHEME_HTTP,
+  };
+
+  // Construct an AttachmentServerURLBuilder that builds URLs with the specified
+  // |scheme|, |host|, and |port|.
+  AttachmentServerURLBuilder(const Scheme& scheme,

[pavely, 2014/05/14 18:38:31]

Do you have a scenario where you'll need to pass all these parameters?
I think likely use of this class is to use one prefix for dev, another for
stable and being able to override it from command line for experiments.
I'd say just pass the whole prefix as string and if in the future we need to do
something more we'll change it.

[maniscalco, 2014/05/14 21:59:03]

We could get away with using a string as a URL prefix.  Done.  I've updated the
patch to drop AttachmentServerURLBuilder and instead pass a url_prefix string. 
LMKWYT.

+                             const std::string& host,
+                             const int port);
+
+  ~AttachmentServerURLBuilder();
+
+  // Default copy and assign welcome.
+
+  // Return a URL to which the attachment identified by |attachment_id| can be
+  // uploaded.
+  GURL BuildUploadURLFor(const AttachmentId& attachment_id) const;
+
+ private:
+  std::string url_prefix_;
+};
+
+}  // namespace syncer
+
+#endif  // SYNC_INTERNAL_API_PUBLIC_ATTACHMENTS_ATTACHMENT_SERVER_URL_BUILDER_H_