Remove third-party cityhash, unused since r8992

src/utils/SkBitmapHasher.cpp

Index: src/utils/SkBitmapHasher.cpp
===================================================================
--- src/utils/SkBitmapHasher.cpp	(revision 9056)
+++ src/utils/SkBitmapHasher.cpp	(working copy)
@@ -10,12 +10,7 @@
 #include "SkEndian.h"
 #include "SkImageEncoder.h"
 
-#ifdef BITMAPHASHER_USES_TRUNCATED_MD5
 #include "SkMD5.h"
-#else
-#include "SkCityHash.h"
-#include "SkStream.h"
-#endif
 
 /**
  * Write an int32 value to a stream in little-endian order.
@@ -37,17 +32,8 @@
 
 /*static*/ bool SkBitmapHasher::ComputeDigestInternal(const SkBitmap& bitmap,
                                                       SkHashDigest *result) {
-#ifdef BITMAPHASHER_USES_TRUNCATED_MD5
     SkMD5 out;
-#else
-    size_t pixelBufferSize = bitmap.width() * bitmap.height() * 4;
-    size_t totalBufferSize = pixelBufferSize + 2 * sizeof(uint32_t);
 
-    SkAutoMalloc bufferManager(totalBufferSize);
-    char *bufferStart = static_cast<char *>(bufferManager.get());
-    SkMemoryWStream out(bufferStart, totalBufferSize);
-#endif
-
     // start with the x/y dimensions
     write_int32_to_buffer(SkToU32(bitmap.width()), &out);
     write_int32_to_buffer(SkToU32(bitmap.height()), &out);
@@ -58,13 +44,9 @@
         return false;
     }
 
-#ifdef BITMAPHASHER_USES_TRUNCATED_MD5
     SkMD5::Digest digest;
     out.finish(digest);
     *result = first_8_bytes_as_uint64(digest.data);
-#else
-    *result = SkCityHash::Compute64(bufferStart, totalBufferSize);
-#endif
     return true;
 }