add new copyTo version to SkBitmap, which takes SkColorType

gm/gmmain.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /*
  * Code for the "gm" (Golden Master) rendering comparison tool.
  *
@@ skipping 275 matching lines @@
                 *bitmap.getAddr32(x, y) |= (SK_A32_MASK << SK_A32_SHIFT);
             }
         }
     }
 
     static ErrorCombination write_bitmap(const SkString& path, const SkBitmap& bitmap) {
         // TODO(epoger): Now that we have removed force_all_opaque()
         // from this method, we should be able to get rid of the
         // transformation to 8888 format also.
         SkBitmap copy;
-        bitmap.copyTo(&copy, SkBitmap::kARGB_8888_Config);
+        bitmap.copyTo(&copy, kPMColor_SkColorType);
         if (!SkImageEncoder::EncodeFile(path.c_str(), copy,
                                         SkImageEncoder::kPNG_Type,
                                         100)) {
             gm_fprintf(stderr, "FAILED to write bitmap: %s\n", path.c_str());
             return ErrorCombination(kWritingReferenceImage_ErrorType);
         }
         return kEmpty_ErrorCombination;
     }
 
     /**
@@ skipping 2113 matching lines @@
     if (FLAGS_forceBWtext) {
         canvas->setDrawFilter(SkNEW(BWTextDrawFilter))->unref();
     }
 }
 
 #if !defined(SK_BUILD_FOR_IOS) && !defined(SK_BUILD_FOR_NACL)
 int main(int argc, char * const argv[]) {
     return tool_main(argc, (char**) argv);
 }
 #endif