Trying to be consistent when members are allowed to be NULL

src/effects/SkColorFilterImageFilter.cpp

Index: src/effects/SkColorFilterImageFilter.cpp
diff --git a/src/effects/SkColorFilterImageFilter.cpp b/src/effects/SkColorFilterImageFilter.cpp
index 2a8df5c672109a4aee428e9801af6c305c0c89d4..ac5ea66586193b5ca74c1e53e7d722b7618dcbb6 100755
--- a/src/effects/SkColorFilterImageFilter.cpp
+++ b/src/effects/SkColorFilterImageFilter.cpp
@@ -62,7 +62,7 @@ SkColorFilterImageFilter* SkColorFilterImageFilter::Create(SkColorFilter* cf,
     SkASSERT(cf);
     SkScalar colorMatrix[20], inputMatrix[20];
     SkColorFilter* inputColorFilter;
-    if (input && cf->asColorMatrix(colorMatrix)
+    if (input && cf && cf->asColorMatrix(colorMatrix)

[sugoi1, 2014/10/29 15:26:12]

SkColorFilterImageFilter's constructor calls SkSafeRef() on cf, so having a NULL
cf is possible (although it will assert in Debug), so we should check for that
here.

[reed1, 2014/10/29 15:43:38]

Does SkColorFilterImageFilter do anything if there is no colorfilter? Why not
just

if (NULL == cf) {
    return NULL;
}

Part of the value of using factories (like Create) is that we can perform these
sorts of safety/optimization checks.

[sugoi1, 2014/10/29 18:21:00]

Done.

               && input->asColorFilter(&inputColorFilter)
               && (inputColorFilter)) {
         SkAutoUnref autoUnref(inputColorFilter);
@@ -141,7 +141,7 @@ bool SkColorFilterImageFilter::asColorFilter(SkColorFilter** filter) const {
     if (!cropRectIsSet()) {
         if (filter) {
             *filter = fColorFilter;
-            fColorFilter->ref();
+            SkSafeRef(fColorFilter);

[sugoi1, 2014/10/29 15:26:12]

SkColorFilterImageFilter's constructor and destructor call SkSafeRef() /
SkSafeUnref() on fColorFilter, so it should be the same here.

         }
         return true;
     }