Remove third-party cityhash, unused since r8992

src/utils/SkCityHash.h

Index: src/utils/SkCityHash.h
===================================================================
--- src/utils/SkCityHash.h	(revision 9056)
+++ src/utils/SkCityHash.h	(working copy)
@@ -1,47 +0,0 @@
-/*
- * Copyright 2012 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-/**
- * Hash functions, using the CityHash algorithm.
- *
- * Results are guaranteed to be:
- *  1. consistent across revisions of the library (for a given set
- *     of bytes, the checksum generated at one revision of the Skia
- *     library will match the one generated on any other revision of
- *     the Skia library)
- *  2. consistent across platforms (for a given
- *     set of bytes, the checksum generated on one platform will
- *     match the one generated on any other platform)
- */
-
-#ifndef SkCityHash_DEFINED
-#define SkCityHash_DEFINED
-
-#include "SkTypes.h"
-
-class SkCityHash : SkNoncopyable {
-public:
-    /**
-     *  Compute a 32-bit checksum for a given data block.
-     *
-     *  @param data Memory address of the data block to be processed.
-     *  @param size Size of the data block in bytes.
-     *  @return checksum result
-     */
-    static uint32_t Compute32(const char *data, size_t size);
-
-    /**
-     *  Compute a 64-bit checksum for a given data block.
-     *
-     *  @param data Memory address of the data block to be processed.
-     *  @param size Size of the data block in bytes.
-     *  @return checksum result
-     */
-    static uint64_t Compute64(const char *data, size_t size);
-};
-
-#endif