Fix colorType/alphaType checks in SkCodec

src/codec/SkBmpMaskCodec.cpp

Index: src/codec/SkBmpMaskCodec.cpp
diff --git a/src/codec/SkBmpMaskCodec.cpp b/src/codec/SkBmpMaskCodec.cpp
index b173317c10a53ef9bee10721978e2b403080ad11..03c16c058896649ae5e9117736e432d6b85208a9 100644
--- a/src/codec/SkBmpMaskCodec.cpp
+++ b/src/codec/SkBmpMaskCodec.cpp
@@ -58,25 +58,12 @@ SkCodec::Result SkBmpMaskCodec::onGetPixels(const SkImageInfo& dstInfo,
     return kSuccess;
 }
 
-bool SkBmpMaskCodec::initializeSwizzler(const SkImageInfo& dstInfo, const Options& options) {
-    // Create the swizzler
-    fMaskSwizzler.reset(SkMaskSwizzler::CreateMaskSwizzler(dstInfo, this->getInfo(), fMasks,
-            this->bitsPerPixel(), options));
-
-    if (nullptr == fMaskSwizzler.get()) {
-        return false;
-    }
-
-    return true;
-}
-
 SkCodec::Result SkBmpMaskCodec::prepareToDecode(const SkImageInfo& dstInfo,
         const SkCodec::Options& options, SkPMColor inputColorPtr[], int* inputColorCount) {
-    // Initialize a the mask swizzler
-    if (!this->initializeSwizzler(dstInfo, options)) {
-        SkCodecPrintf("Error: cannot initialize swizzler.\n");
-        return SkCodec::kInvalidConversion;
-    }
+    // Initialize the mask swizzler
+    fMaskSwizzler.reset(SkMaskSwizzler::CreateMaskSwizzler(dstInfo, this->getInfo(), fMasks,
+            this->bitsPerPixel(), options));
+    SkASSERT(fMaskSwizzler);
 
     return SkCodec::kSuccess;
 }