Trying to be consistent when members are allowed to be NULL

src/effects/SkRectShaderImageFilter.cpp

Index: src/effects/SkRectShaderImageFilter.cpp
diff --git a/src/effects/SkRectShaderImageFilter.cpp b/src/effects/SkRectShaderImageFilter.cpp
index fb34ed0007152f124ae557a5567aad4effa3bed5..09417c8840f9fe8c0ef3ae6cfe1a789ed4064e56 100644
--- a/src/effects/SkRectShaderImageFilter.cpp
+++ b/src/effects/SkRectShaderImageFilter.cpp
@@ -20,20 +20,18 @@ SkRectShaderImageFilter* SkRectShaderImageFilter::Create(SkShader* s, const SkRe
         flags = 0x0;
     }
     CropRect cropRect(rect, flags);
-    return SkNEW_ARGS(SkRectShaderImageFilter, (s, &cropRect));
+    return s ? SkNEW_ARGS(SkRectShaderImageFilter, (s, &cropRect)) : NULL;
 }
 
 SkRectShaderImageFilter* SkRectShaderImageFilter::Create(SkShader* s, const CropRect* cropRect, uint32_t uniqueID) {
     SkASSERT(s);
-    return SkNEW_ARGS(SkRectShaderImageFilter, (s, cropRect, uniqueID));
+    return s ? SkNEW_ARGS(SkRectShaderImageFilter, (s, cropRect, uniqueID)) : NULL;
 }
 
 SkRectShaderImageFilter::SkRectShaderImageFilter(SkShader* s, const CropRect* cropRect,
                                                  uint32_t uniqueID)
   : INHERITED(0, NULL, cropRect, uniqueID)
-  , fShader(s) {
-    SkASSERT(s);
-    s->ref();
+  , fShader(SkRef(s)) {
 }
 
 #ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
@@ -55,7 +53,7 @@ void SkRectShaderImageFilter::flatten(SkWriteBuffer& buffer) const {
 }
 
 SkRectShaderImageFilter::~SkRectShaderImageFilter() {
-    SkSafeUnref(fShader);
+    fShader->unref();
 }
 
 bool SkRectShaderImageFilter::onFilterImage(Proxy* proxy,
@@ -78,7 +76,7 @@ bool SkRectShaderImageFilter::onFilterImage(Proxy* proxy,
     SkPaint paint;
     SkMatrix matrix(ctx.ctm());
     matrix.postTranslate(SkIntToScalar(-bounds.left()), SkIntToScalar(-bounds.top()));
-    paint.setShader(SkShader::CreateLocalMatrixShader(fShader, matrix))->unref();
+    SkSafeUnref(paint.setShader(SkShader::CreateLocalMatrixShader(fShader, matrix)));
 
     SkRect rect = SkRect::MakeWH(SkIntToScalar(bounds.width()), SkIntToScalar(bounds.height()));
     canvas.drawRect(rect, paint);