Check for no pixels after calling lockPixels(). If so, we return rather than

ui/gfx/color_utils.cc

 // Copyright (c) 2011 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 190 matching lines @@
   return (abs(r - average) < kAverageBoundary) &&
          (abs(g - average) < kAverageBoundary) &&
          (abs(b - average) < kAverageBoundary);
 }
 
 SkColor GetAverageColorOfFavicon(SkBitmap* favicon, SkAlpha alpha) {
   int r = 0, g = 0, b = 0;
 
   SkAutoLockPixels favicon_lock(*favicon);
   SkColor* pixels = static_cast<SkColor*>(favicon->getPixels());
+  if (!pixels)
+    return SkColorSetARGB(alpha, 0, 0, 0);
+
   // Assume ARGB_8888 format.
   DCHECK(favicon->getConfig() == SkBitmap::kARGB_8888_Config);
   SkColor* current_color = pixels;
 
   DCHECK(favicon->width() <= 16 && favicon->height() <= 16);
 
   int pixel_count = favicon->width() * favicon->height();
   int color_count = 0;
   for (int i = 0; i < pixel_count; ++i, ++current_color) {
     // Disregard this color if it is close to black, close to white, or close
@@ skipping 13 matching lines @@
     ++color_count;
   }
 
   return color_count ?
       SkColorSetARGB(alpha, r / color_count, g / color_count, b / color_count) :
       SkColorSetARGB(alpha, 0, 0, 0);
 }
 
 void BuildLumaHistogram(SkBitmap* bitmap, int histogram[256]) {
   SkAutoLockPixels bitmap_lock(*bitmap);
+  if (!bitmap->getPixels())
+    return;
+
   // Assume ARGB_8888 format.
   DCHECK(bitmap->getConfig() == SkBitmap::kARGB_8888_Config);
 
   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)]++;
   }
@@ skipping 39 matching lines @@
 SkColor GetSysSkColor(int which) {
 #if defined(OS_WIN)
   return skia::COLORREFToSkColor(GetSysColor(which));
 #else
   NOTIMPLEMENTED();
   return SK_ColorLTGRAY;
 #endif
 }
 
 }  // namespace color_utils