Delete dead code. SkBitmapHasher has not been used since gm.

tests/BitmapHasherTest.cpp

-/*
- * Copyright 2013 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "SkBitmapHasher.h"
-
-#include "SkBitmap.h"
-#include "SkColor.h"
-#include "Test.h"
-
-// Word size that is large enough to hold results of any checksum type.
-typedef uint64_t checksum_result;
-
-// Fill in bitmap with test data.
-static void CreateTestBitmap(SkBitmap* bitmap, int width, int height,
-                             SkColor color, skiatest::Reporter* reporter) {
-    bitmap->allocN32Pixels(width, height, kOpaque_SkAlphaType);
-    bitmap->eraseColor(color);
-}
-
-DEF_TEST(BitmapHasher, reporter) {
-    // Test SkBitmapHasher
-    SkBitmap bitmap;
-    uint64_t digest;
-    // initial test case
-    CreateTestBitmap(&bitmap, 333, 555, SK_ColorBLUE, reporter);
-    REPORTER_ASSERT(reporter, SkBitmapHasher::ComputeDigest(bitmap, &digest));
-    REPORTER_ASSERT(reporter, digest == 0xfb2903562766ef87ULL);
-    // same pixel data but different dimensions should yield a different checksum
-    CreateTestBitmap(&bitmap, 555, 333, SK_ColorBLUE, reporter);
-    REPORTER_ASSERT(reporter, SkBitmapHasher::ComputeDigest(bitmap, &digest));
-    REPORTER_ASSERT(reporter, digest == 0xfe04023fb97d0f61ULL);
-    // same dimensions but different color should yield a different checksum
-    CreateTestBitmap(&bitmap, 555, 333, SK_ColorGREEN, reporter);
-    REPORTER_ASSERT(reporter, SkBitmapHasher::ComputeDigest(bitmap, &digest));
-    REPORTER_ASSERT(reporter, digest == 0x2423c51cad6d1edcULL);
-}