Enable skia asserts. They were disabled some time ago due to...

skia/ext/image_operations_unittest.cc

 // Copyright (c) 2006-2008 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.
 
 #include <stdlib.h>
 
 #include "skia/ext/image_operations.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkColorPriv.h"
@@ skipping 186 matching lines @@
 
   SkBitmap src;
   FillDataToBitmap(src_w, src_h, &src);
 
   // Generate alpha mask
   SkBitmap alpha;
   alpha.setConfig(SkBitmap::kARGB_8888_Config, src_w, src_h);
   alpha.allocPixels();
   for (int y = 0, i = 0; y < src_h; y++) {
     for (int x = 0; x < src_w; x++) {
-      *alpha.getAddr32(x, y) = SkColorSetARGB(i + 128 % 255,
-                                              i + 128 % 255,
-                                              i + 64 % 255,
-                                              i + 0 % 255);
+      *alpha.getAddr32(x, y) = SkColorSetARGB((i + 128) % 255,
+                                              (i + 128) % 255,
+                                              (i + 64) % 255,
+                                              (i + 0) % 255);
       i++;
     }
   }
 
   SkBitmap masked = skia::ImageOperations::CreateMaskedBitmap(src, alpha);
 
   SkAutoLockPixels src_lock(src);
   SkAutoLockPixels alpha_lock(alpha);
   SkAutoLockPixels masked_lock(masked);
   for (int y = 0; y < src_h; y++) {
@@ skipping 288 matching lines @@
   // Test multiple steps of downsampling.
   SkBitmap large;
   large.setConfig(SkBitmap::kARGB_8888_Config, 100, 43);
   large.allocPixels();
   result = skia::ImageOperations::DownsampleByTwoUntilSize(large, 6, 6);
 
   // The result should be divided in half 100x43 -> 50x22 -> 25x11
   EXPECT_EQ(25, result.width());
   EXPECT_EQ(11, result.height());
 }