Trying to be consistent when members are allowed to be NULL

src/effects/SkColorFilterImageFilter.cpp

 /*
  * Copyright 2012 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 "SkColorFilterImageFilter.h"
 #include "SkBitmap.h"
 #include "SkCanvas.h"
@@ skipping 42 matching lines @@
         || component_needs_clamping(matrix+5)
         || component_needs_clamping(matrix+10)
         || component_needs_clamping(matrix+15);
 }
 
 };
 
 SkColorFilterImageFilter* SkColorFilterImageFilter::Create(SkColorFilter* cf,
         SkImageFilter* input, const CropRect* cropRect, uint32_t uniqueID) {
     SkASSERT(cf);
+    if (NULL == cf) {
+        return NULL;
+    }
     SkScalar colorMatrix[20], inputMatrix[20];
     SkColorFilter* inputColorFilter;
     if (input && cf->asColorMatrix(colorMatrix)
               && input->asColorFilter(&inputColorFilter)
               && (inputColorFilter)) {
         SkAutoUnref autoUnref(inputColorFilter);
         if (inputColorFilter->asColorMatrix(inputMatrix) && !matrix_needs_clamping(inputMatrix)) {
             SkScalar combinedMatrix[20];
             mult_color_matrix(colorMatrix, inputMatrix, combinedMatrix);
             SkAutoTUnref<SkColorFilter> newCF(SkColorMatrixFilter::Create(combinedMatrix));
             return SkNEW_ARGS(SkColorFilterImageFilter, (newCF, input->getInput(0), cropRect, 0));
         }
     }
     return SkNEW_ARGS(SkColorFilterImageFilter, (cf, input, cropRect, uniqueID));
 }
 
 SkColorFilterImageFilter::SkColorFilterImageFilter(SkColorFilter* cf,
         SkImageFilter* input, const CropRect* cropRect, uint32_t uniqueID)
-    : INHERITED(1, &input, cropRect, uniqueID), fColorFilter(cf) {
-    SkASSERT(cf);
-    SkSafeRef(cf);
+    : INHERITED(1, &input, cropRect, uniqueID), fColorFilter(SkRef(cf)) {
 }
 
 #ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
 SkColorFilterImageFilter::SkColorFilterImageFilter(SkReadBuffer& buffer)
   : INHERITED(1, buffer) {
     fColorFilter = buffer.readColorFilter();
 }
 #endif
 
 SkFlattenable* SkColorFilterImageFilter::CreateProc(SkReadBuffer& buffer) {
     SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
     SkAutoTUnref<SkColorFilter> cf(buffer.readColorFilter());
     return Create(cf, common.getInput(0), &common.cropRect(), common.uniqueID());
 }
 
 void SkColorFilterImageFilter::flatten(SkWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
     buffer.writeFlattenable(fColorFilter);
 }
 
 SkColorFilterImageFilter::~SkColorFilterImageFilter() {
-    SkSafeUnref(fColorFilter);
+    fColorFilter->unref();
 }
 
 bool SkColorFilterImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& source,
                                              const Context& ctx,
                                              SkBitmap* result,
                                              SkIPoint* offset) const {
     SkBitmap src = source;
     SkIPoint srcOffset = SkIPoint::Make(0, 0);
     if (getInput(0) && !getInput(0)->filterImage(proxy, source, ctx, &src, &srcOffset)) {
         return false;
@@ skipping 24 matching lines @@
 bool SkColorFilterImageFilter::asColorFilter(SkColorFilter** filter) const {
     if (!cropRectIsSet()) {
         if (filter) {
             *filter = fColorFilter;
             fColorFilter->ref();
         }
         return true;
     }
     return false;
 }