BuildLumaHistogram() attempts to access Skia pixel data directly. This isn't

ui/gfx/color_utils.cc

 // Copyright (c) 2012 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 "ui/gfx/color_utils.h"
 
 #include <math.h>
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
@@ skipping 179 matching lines @@
   return SkColorSetARGB(alpha,
                         static_cast<int>(r),
                         static_cast<int>(g),
                         static_cast<int>(b));
 }
 
 void BuildLumaHistogram(const SkBitmap& bitmap, int histogram[256]) {
   DCHECK_EQ(SkBitmap::kARGB_8888_Config, bitmap.config());
 
   SkAutoLockPixels bitmap_lock(bitmap);
-  if (!bitmap.getPixels())
-    return;
 
   int pixel_width = bitmap.width();
   int pixel_height = bitmap.height();
   for (int y = 0; y < pixel_height; ++y) {
-    SkColor* current_color = static_cast<uint32_t*>(bitmap.getAddr32(0, y));
-    for (int x = 0; x < pixel_width; ++x, ++current_color)
-      histogram[GetLuminanceForColor(*current_color)]++;
+    for (int x = 0; x < pixel_width; ++x)
+      ++histogram[GetLuminanceForColor(bitmap.getColor(x, y))];
   }
 }
 
 SkColor AlphaBlend(SkColor foreground, SkColor background, SkAlpha alpha) {
   if (alpha == 0)
     return background;
   if (alpha == 255)
     return foreground;
 
   int f_alpha = SkColorGetA(foreground);
@@ skipping 38 matching lines @@
 SkColor GetSysSkColor(int which) {
 #if defined(OS_WIN)
   return skia::COLORREFToSkColor(GetSysColor(which));
 #else
   NOTIMPLEMENTED();
   return SK_ColorLTGRAY;
 #endif
 }
 
 }  // namespace color_utils