Revert "Revert "cache SkImage::Info calculation in lazypixelref""

src/images/SkImageDecoder.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkImageDecoder.h"
 #include "SkBitmap.h"
@@ skipping 387 matching lines @@
         return false;
     }
 
     bitmap->swap(bm8888);
     return true;
 }
 
 bool SkImageDecoder::DecodeMemoryToTarget(const void* buffer, size_t size,
                                           SkImage::Info* info,
                                           const SkBitmapFactory::Target* target) {
-    if (NULL == info) {
-        return false;
-    }
-
     // FIXME: Just to get this working, implement in terms of existing
     // ImageDecoder calls.
     SkBitmap bm;
     SkMemoryStream stream(buffer, size);
     SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(&stream));
     if (NULL == decoder.get()) {
         return false;
     }
 
     if (!decode_bounds_to_8888(decoder.get(), &stream, &bm)) {
         return false;
     }
 
     SkASSERT(bm.config() == SkBitmap::kARGB_8888_Config);
 
     // Now set info properly.
     // Since Config is SkBitmap::kARGB_8888_Config, SkBitmapToImageInfo
     // will always succeed.
-    SkAssertResult(SkBitmapToImageInfo(bm, info));
+    if (info) {
+        SkAssertResult(SkBitmapToImageInfo(bm, info));
+    }
 
     if (NULL == target) {
         return true;
     }
 
     if (target->fRowBytes != SkToU32(bm.rowBytes())) {
-        if (target->fRowBytes < SkImageMinRowBytes(*info)) {
+        size_t minRB = SkBitmap::ComputeRowBytes(bm.config(), bm.width());
+        if (target->fRowBytes < minRB) {
             SkDEBUGFAIL("Desired row bytes is too small");
             return false;
         }
         bm.setConfig(bm.config(), bm.width(), bm.height(), target->fRowBytes);
     }
 
     // SkMemoryStream.rewind() will always return true.
     SkAssertResult(stream.rewind());
     return decode_pixels_to_8888(decoder.get(), &stream, &bm, target->fAddr);
 }
@@ skipping 15 matching lines @@
             if (kUnknown_Format == *format) {
                 if (stream->rewind()) {
                     *format = GetStreamFormat(stream);
                 }
             }
         }
         delete codec;
     }
     return success;
 }