Initial error handling code

src/effects/SkBlurImageFilter.cpp

 /*
  * Copyright 2011 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkBlurImageFilter.h"
 #include "SkColorPriv.h"
 #include "SkFlattenableBuffers.h"
 #include "SkGpuBlurUtils.h"
 #if SK_SUPPORT_GPU
 #include "GrContext.h"
 #include "SkImageFilterUtils.h"
 #endif
 
 SkBlurImageFilter::SkBlurImageFilter(SkFlattenableReadBuffer& buffer)
   : INHERITED(buffer) {
     fSigma.fWidth = buffer.readScalar();
     fSigma.fHeight = buffer.readScalar();
+    buffer.validate(SkScalarIsFinite(fSigma.fWidth) &&
+                    SkScalarIsFinite(fSigma.fHeight) &&
+                    (fSigma.fWidth >= 0) &&
+                    (fSigma.fHeight >= 0));
 }
 
 SkBlurImageFilter::SkBlurImageFilter(SkScalar sigmaX,
                                      SkScalar sigmaY,
                                      SkImageFilter* input,
                                      const CropRect* cropRect)
     : INHERITED(input, cropRect), fSigma(SkSize::Make(sigmaX, sigmaY)) {
     SkASSERT(sigmaX >= 0 && sigmaY >= 0);
 }
 
@@ skipping 195 matching lines @@
                                                              fSigma.width(),
                                                              fSigma.height()));
     offset->fX += rect.fLeft;
     offset->fY += rect.fTop;
     return SkImageFilterUtils::WrapTexture(tex, rect.width(), rect.height(), result);
 #else
     SkDEBUGFAIL("Should not call in GPU-less build");
     return false;
 #endif
 }