Finish supporting decoding opaque to non-opaque

src/codec/SkWbmpCodec.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCodec.h"
 #include "SkCodecPriv.h"
 #include "SkColorPriv.h"
@@ skipping 12 matching lines @@
 
 static inline void setup_color_table(SkColorType colorType,
         SkPMColor* colorPtr, int* colorCount) {
     if (kIndex_8_SkColorType == colorType) {
         colorPtr[0] = SK_ColorBLACK;
         colorPtr[1] = SK_ColorWHITE;
         *colorCount = 2;
     }
 }
 
-static inline bool valid_color_type(SkColorType colorType, SkAlphaType alphaType) {
+static inline bool valid_color_type(SkColorType colorType) {
     switch (colorType) {
         case kRGBA_8888_SkColorType:
         case kBGRA_8888_SkColorType:
         case kIndex_8_SkColorType:
-            return true;
         case kGray_8_SkColorType:
         case kRGB_565_SkColorType:
-            return kOpaque_SkAlphaType == alphaType;
+            return true;
         default:
             return false;
     }
 }
 
 static bool read_byte(SkStream* stream, uint8_t* data)
 {
     return stream->read(data, 1) == 1;
 }
 
@@ skipping 69 matching lines @@
                                          size_t rowBytes,
                                          const Options& options,
                                          SkPMColor ctable[],
                                          int* ctableCount,
                                          int* rowsDecoded) {
     if (options.fSubset) {
         // Subsets are not supported.
         return kUnimplemented;
     }
 
-    if (!valid_color_type(info.colorType(), info.alphaType()) ||
+    if (!valid_color_type(info.colorType()) ||
             !valid_alpha(info.alphaType(), this->getInfo().alphaType())) {
         return kInvalidConversion;
     }
 
     // Prepare a color table if necessary
     setup_color_table(info.colorType(), ctable, ctableCount);
 
     // Initialize the swizzler
     SkAutoTDelete<SkSwizzler> swizzler(this->initializeSwizzler(info, ctable, options));
     SkASSERT(swizzler);
@@ skipping 47 matching lines @@
     return this->stream()->skip(bytesToSkip) == bytesToSkip;
 }
 
 SkCodec::Result SkWbmpCodec::onStartScanlineDecode(const SkImageInfo& dstInfo,
         const Options& options, SkPMColor inputColorTable[], int* inputColorCount) {
     if (options.fSubset) {
         // Subsets are not supported.
         return kUnimplemented;
     }
 
-    if (!valid_color_type(dstInfo.colorType(), dstInfo.alphaType()) ||
+    if (!valid_color_type(dstInfo.colorType()) ||
             !valid_alpha(dstInfo.alphaType(), this->getInfo().alphaType())) {
         return kInvalidConversion;
     }
 
     // Fill in the color table
     setup_color_table(dstInfo.colorType(), inputColorTable, inputColorCount);
 
     // Copy the color table to a pointer that can be owned by the scanline decoder
     if (kIndex_8_SkColorType == dstInfo.colorType()) {
         fColorTable.reset(new SkColorTable(inputColorTable, 2));
     }
 
     // Initialize the swizzler
     fSwizzler.reset(this->initializeSwizzler(dstInfo, get_color_ptr(fColorTable.get()), options));
     SkASSERT(fSwizzler);
 
     fSrcBuffer.reset(fSrcRowBytes);
 
     return kSuccess;
 }