make info real in SkPixelRef, and add bitmap::asImageInfo

src/images/SkDecodingImageGenerator.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkDecodingImageGenerator.h"
 #include "SkData.h"
 #include "SkDiscardablePixelRef.h"
@@ skipping 101 matching lines @@
         return false;
     }
     SkBitmap bitmap;
     if (!decoder->decode(fStream, &bitmap,
                          SkImageDecoder::kDecodeBounds_Mode)) {
         return false;
     }
     if (bitmap.config() == SkBitmap::kNo_Config) {
         return false;
     }
-    if (!SkBitmapToImageInfo(bitmap, &fInfo)) {
+    if (!bitmap.asImageInfo(&fInfo)) {
         // We can't use bitmap.config() as is.
-        // Must be kARGB_4444_Config.
         if (!bitmap.canCopyTo(SkBitmap::kARGB_8888_Config)) {
-            // kARGB_4444_Config can copy to kARGB_8888.
             SkDEBUGFAIL("!bitmap->canCopyTo(SkBitmap::kARGB_8888_Config)");
             return false;
         }
         fDoCopyTo = true;
         fInfo.fWidth = bitmap.width();
         fInfo.fHeight = bitmap.height();
         fInfo.fColorType = kPMColor_SkColorType;
         fInfo.fAlphaType = bitmap.alphaType();
     }
     if (info != NULL) {
@@ skipping 65 matching lines @@
     SkASSERT(stream != NULL);
     SkASSERT(dst != NULL);
     if ((stream == NULL) || !stream->unique()) {
         SkSafeUnref(stream);
         return false;
     }
     SkImageGenerator* gen(SkNEW_ARGS(SkDecodingImageGenerator, (stream)));
     return SkDiscardablePixelRef::Install(gen, dst, factory);
 }