unify peekPixels around pixmap parameter

src/core/SkSpecialImage.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file
  */
 
 #include "SkCanvas.h"
 #include "SkImage_Base.h"
 #include "SkSpecialImage.h"
@@ skipping 96 matching lines @@
 
     bool isOpaque() const override { return fImage->isOpaque(); }
 
     size_t getSize() const override {
 #if SK_SUPPORT_GPU
         if (GrTexture* texture = as_IB(fImage.get())->peekTexture()) {
             return texture->gpuMemorySize();
         } else
 #endif
         {
-            SkImageInfo info;
-            size_t rowBytes;
-
-            if (fImage->peekPixels(&info, &rowBytes)) {
-                return info.height() * rowBytes;
+            SkPixmap pm;
+            if (fImage->peekPixels(&pm)) {
+                return pm.height() * pm.rowBytes();
             }
         }
         return 0;
     }
 
     void onDraw(SkCanvas* canvas, SkScalar x, SkScalar y, const SkPaint* paint) const override {
         SkRect dst = SkRect::MakeXYWH(x, y, this->subset().width(), this->subset().height());
 
         canvas->drawImageRect(fImage, this->subset(),
                               dst, paint, SkCanvas::kStrict_SrcRectConstraint);
@@ skipping 235 matching lines @@
 
 SkSpecialImage* SkSpecialImage::NewFromGpu(SkImageFilter::Proxy* proxy,
                                            const SkIRect& subset,
                                            uint32_t uniqueID,
                                            GrTexture* tex,
                                            SkAlphaType at) {
     return nullptr;
 }
 
 #endif