Adding more validation

src/effects/SkDropShadowImageFilter.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 "SkDropShadowImageFilter.h"
 
 #include "SkBitmap.h"
 #include "SkBlurImageFilter.h"
 #include "SkCanvas.h"
 #include "SkColorMatrixFilter.h"
 #include "SkDevice.h"
 #include "SkFlattenableBuffers.h"
 
 SkDropShadowImageFilter::SkDropShadowImageFilter(SkScalar dx, SkScalar dy, SkScalar sigma, SkColor color, SkImageFilter* input)
     : SkImageFilter(input)
     , fDx(dx)
     , fDy(dy)
     , fSigma(sigma)
     , fColor(color)
 {
 }
 
-SkDropShadowImageFilter::SkDropShadowImageFilter(SkFlattenableReadBuffer& buffer) : INHERITED(buffer)
-{
+SkDropShadowImageFilter::SkDropShadowImageFilter(SkFlattenableReadBuffer& buffer)
+ : INHERITED(1, buffer) {
     fDx = buffer.readScalar();
     fDy = buffer.readScalar();
     fSigma = buffer.readScalar();
     fColor = buffer.readColor();
     buffer.validate(SkScalarIsFinite(fDx) &&
                     SkScalarIsFinite(fDy) &&
                     SkScalarIsFinite(fSigma));
 }
 
 void SkDropShadowImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const
@@ skipping 18 matching lines @@
     SkAutoTUnref<SkColorFilter> colorFilter(SkColorFilter::CreateModeFilter(fColor, SkXfermode::kSrcIn_Mode));
     SkPaint paint;
     paint.setImageFilter(blurFilter.get());
     paint.setColorFilter(colorFilter.get());
     paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
     canvas.drawBitmap(src, fDx, fDy, &paint);
     canvas.drawBitmap(src, 0, 0);
     *result = device->accessBitmap(false);
     return true;
 }