add peekPixels to SkCanvas and SkSurface

gm/matrixconvolution.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 "gm.h"
 #include "SkColor.h"
 #include "SkMatrixConvolutionImageFilter.h"
 #include "SkGradientShader.h"
 
 namespace skiagm {
 
 class MatrixConvolutionGM : public GM {
 public:
     MatrixConvolutionGM() : fInitialized(false) {
         this->setBGColor(0x00000000);
     }
 
 protected:
     virtual SkString onShortName() {
         return SkString("matrixconvolution");
     }
 
     void make_bitmap() {
         fBitmap.allocN32Pixels(80, 80);
-        SkBitmapDevice device(fBitmap);
-        SkCanvas canvas(&device);
+        SkCanvas canvas(fBitmap);
         canvas.clear(0x00000000);
         SkPaint paint;
         paint.setAntiAlias(true);
         paint.setColor(0xFFFFFFFF);
         paint.setTextSize(SkIntToScalar(180));
         SkPoint pts[2] = { SkPoint::Make(0, 0),
                            SkPoint::Make(0, SkIntToScalar(80)) };
         SkColor colors[2] = { 0xFFFFFFFF, 0x40404040 };
         SkScalar pos[2] = { 0, SkIntToScalar(80) };
         paint.setShader(SkGradientShader::CreateLinear(
@@ skipping 67 matching lines @@
     SkBitmap fBitmap;
     bool fInitialized;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static GM* MyFactory(void*) { return new MatrixConvolutionGM; }
 static GMRegistry reg(MyFactory);
 
 }