add peekPixels to SkCanvas and SkSurface

gm/xfermodes3.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 "gm.h"
 #include "SkBitmap.h"
 #include "SkGradientShader.h"
@@ skipping 150 matching lines @@
         SkPaint bgPaint;
         bgPaint.setAntiAlias(false);
         bgPaint.setShader(fBGShader);
         modeCanvas->drawRect(r, bgPaint);
         modeCanvas->drawRect(r, modePaint);
         modeCanvas = NULL;
 
         if (NULL == layerCanvas) {
             canvas->restore();
         } else {
-            SkBitmap bitmap = layerCanvas->getDevice()->accessBitmap(false);
-            canvas->drawBitmap(bitmap, 0, 0);
+            SkAutoROCanvasPixels ropixels(layerCanvas);
+            SkBitmap bitmap;
+            if (ropixels.asROBitmap(&bitmap)) {
+                canvas->drawBitmap(bitmap, 0, 0);
+            }
         }
 
         r.inset(-SK_ScalarHalf, -SK_ScalarHalf);
         SkPaint borderPaint;
         borderPaint.setStyle(SkPaint::kStroke_Style);
         canvas->drawRect(r, borderPaint);
 
         canvas->restore();
     }
 
@@ skipping 51 matching lines @@
     SkAutoTUnref<SkShader> fBmpShader;
 
     typedef GM INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 DEF_GM(return new Xfermodes3GM;)
 
 }