Expand pixelref to return SkImageInfo and rowbytes

src/gpu/GrSurface.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrSurface.h"
 
 #include "SkBitmap.h"
+#include "SkGr.h"
 #include "SkImageEncoder.h"
 #include <stdio.h>
 
 SK_DEFINE_INST_COUNT(GrSurface)
 
+void GrSurface::asImageInfo(SkImageInfo* info) const {
+    if (!GrPixelConfig2ColorType(this->config(), &info->fColorType)) {
+        sk_throw();
+    }
+    info->fWidth = this->width();
+    info->fHeight = this->height();
+    info->fAlphaType = kPremul_SkAlphaType;
+}
+
 bool GrSurface::savePixels(const char* filename) {
     SkBitmap bm;
     bm.setConfig(SkBitmap::kARGB_8888_Config, this->width(), this->height());
     bm.allocPixels();
 
     bool result = readPixels(0, 0, this->width(), this->height(), kSkia8888_GrPixelConfig,
                              bm.getPixels());
     if (!result) {
         SkDebugf("------ failed to read pixels for %s\n", filename);
         return false;
     }
 
     // remove any previous version of this file
     remove(filename);
 
     if (!SkImageEncoder::EncodeFile(filename, bm, SkImageEncoder::kPNG_Type, 100)) {
         SkDebugf("------ failed to encode %s\n", filename);
         remove(filename);   // remove any partial file
         return false;
     }
 
     return true;
 }