Change some more GMs to clear to opaque black, not transparent black.

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"
@@ skipping 66 matching lines @@
         canvas->restore();
     }
 
     typedef SkMatrixConvolutionImageFilter MCIF;
 
     virtual void onDraw(SkCanvas* canvas) {
         if (!fInitialized) {
             make_bitmap();
             fInitialized = true;
         }
-        canvas->clear(0x00000000);
+        canvas->clear(SK_ColorBLACK);
         SkIPoint kernelOffset = SkIPoint::Make(1, 0);
         for (int x = 10; x < 310; x += 100) {
             this->draw(canvas, x, 10, kernelOffset, MCIF::kClamp_TileMode, true);
             this->draw(canvas, x, 110, kernelOffset, MCIF::kClampToBlack_TileMode, true);
             this->draw(canvas, x, 210, kernelOffset, MCIF::kRepeat_TileMode, true);
             kernelOffset.fY++;
         }
         kernelOffset.fY = 1;
         SkImageFilter::CropRect rect(SkRect::MakeXYWH(10, 5, 60, 60));
         this->draw(canvas, 310, 10, kernelOffset, MCIF::kClamp_TileMode, true, &rect);
@@ skipping 10 matching lines @@
     SkBitmap fBitmap;
     bool fInitialized;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static GM* MyFactory(void*) { return new MatrixConvolutionGM; }
 static GMRegistry reg(MyFactory);
 
 }