Add a PNGEncoder helper function that takes an SkBitmap,

chrome/common/security_filter_peer.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 "chrome/common/security_filter_peer.h"
 
 #include "base/gfx/png_encoder.h"
 #include "base/gfx/size.h"
 #include "base/string_util.h"
 #include "net/base/net_errors.h"
@@ skipping 280 matching lines @@
          x += stamp_bitmap->width() * 2) {
       canvas.drawBitmap(*stamp_bitmap,
                         SkIntToScalar(x),
                         SkIntToScalar(row * stamp_bitmap->height()),
                         &paint);
     }
   }
 
   // Now encode it to a PNG.
   std::vector<unsigned char> output;
-  unsigned char* input =
-      static_cast<unsigned char*>(canvas.getDevice()->accessBitmap(false).
-          getPixels());
-  if (!PNGEncoder::Encode(input,
-                          PNGEncoder::FORMAT_BGRA,
-                          image.width(), image.height(),
-                          image.width() * 4, false, &output)) {
+  if (!PNGEncoder::EncodeBGRASkBitmap(canvas.getDevice()->accessBitmap(false),
+                                      false, &output)) {
     return false;
   }
 
   // Copy the vector content to data_ which is a string.
   data_.clear();
   data_.resize(output.size());
   std::copy(output.begin(), output.end(), data_.begin());
 
   return true;
 }