Remove the flash specific disk cache backend.

net/disk_cache/flash/format.h

-// Copyright (c) 2011 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 NET_DISK_CACHE_FLASH_FORMAT_H_
-#define NET_DISK_CACHE_FLASH_FORMAT_H_
-
-namespace disk_cache {
-
-// Storage constants.
-const int32 kFlashPageSize = 8 * 1024;
-const int32 kFlashBlockSize = 512 * kFlashPageSize;
-
-// Segment constants.
-const int32 kFlashSegmentSize = 4 * 1024 * 1024;
-const int32 kFlashSmallEntrySize = 4 * 1024;
-const size_t kFlashMaxEntryCount = kFlashSegmentSize / kFlashSmallEntrySize - 1;
-
-// Segment summary consists of a fixed region at the end of the segment
-// containing a counter specifying the number of saved offsets followed by the
-// offsets.
-const int32 kFlashSummarySize = (1 + kFlashMaxEntryCount) * sizeof(int32);
-const int32 kFlashSegmentFreeSpace = kFlashSegmentSize - kFlashSummarySize;
-
-// An entry consists of a fixed number of streams.
-const int32 kFlashLogStoreEntryNumStreams = 4;
-const int32 kFlashLogStoreEntryHeaderSize =
-    kFlashLogStoreEntryNumStreams * sizeof(int32);
-
-}  // namespace disk_cache
-
-#endif  // NET_DISK_CACHE_FLASH_FORMAT_H_