Store attachment crc in AttachmentStore

sync/internal_api/public/attachments/attachment_uploader_impl.h

 // 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_UPLOADER_IMPL_H_
 #define SYNC_INTERNAL_API_PUBLIC_ATTACHMENTS_ATTACHMENT_UPLOADER_IMPL_H_
 
 #include "base/containers/scoped_ptr_hash_map.h"
 #include "base/gtest_prod_util.h"
 #include "base/threading/non_thread_safe.h"
@@ skipping 33 matching lines @@
   ~AttachmentUploaderImpl() override;
 
   // AttachmentUploader implementation.
   void UploadAttachment(const Attachment& attachment,
                         const UploadCallback& callback) override;
 
   // Return the URL for the given |sync_service_url| and |attachment_id|.
   static GURL GetURLForAttachmentId(const GURL& sync_service_url,
                                     const AttachmentId& attachment_id);
 
-  // Return the crc32c of the memory described by |data| and |size|.
+  // Format crc32c to pass into X-Goog-Hash header

[maniscalco, 2014/11/11 00:44:54]

nit: needs a period at the end.

[pavely, 2014/11/11 22:27:15]

Done.

   //
   // The value is base64 encoded, big-endian format.  Suitable for use in the
   // X-Goog-Hash header
   // (https://cloud.google.com/storage/docs/reference-headers#xgooghash).
-  //
-  // Potentially expensive.
-  static std::string ComputeCrc32cHash(const char* data, size_t size);
+  static std::string FormatCrc32cHash(uint32_t crc);
 
  private:
   class UploadState;
   typedef std::string UniqueId;
   typedef base::ScopedPtrHashMap<UniqueId, UploadState> StateMap;
 
   void OnUploadStateStopped(const UniqueId& unique_id);
 
   GURL sync_service_url_;
   scoped_refptr<net::URLRequestContextGetter> url_request_context_getter_;
   std::string account_id_;
   OAuth2TokenService::ScopeSet scopes_;
   scoped_refptr<OAuth2TokenServiceRequest::TokenServiceProvider>
       token_service_provider_;
   StateMap state_map_;
 
   // Must be last data member.
   base::WeakPtrFactory<AttachmentUploaderImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(AttachmentUploaderImpl);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_ATTACHMENTS_ATTACHMENT_UPLOADER_IMPL_H_