Add subsetting to SkScaledCodec

src/codec/SkCodec_wbmp.cpp

Index: src/codec/SkCodec_wbmp.cpp
diff --git a/src/codec/SkCodec_wbmp.cpp b/src/codec/SkCodec_wbmp.cpp
index af22e402ae64a40a0993ac83bb8879e20c8fae3d..ed3db50e6622c4a87a3591d61b460ba0f4582c9d 100644
--- a/src/codec/SkCodec_wbmp.cpp
+++ b/src/codec/SkCodec_wbmp.cpp
@@ -71,16 +71,16 @@ bool SkWbmpCodec::onRewind() {
     return read_header(this->stream(), nullptr);
 }
 
-SkSwizzler* SkWbmpCodec::initializeSwizzler(const SkImageInfo& info,
-        const SkPMColor* ctable, const Options& opts) {
+SkSwizzler* SkWbmpCodec::initializeSwizzler(const SkImageInfo& info, const SkPMColor* ctable,
+        const Options& opts, int subsetLeft, int subsetWidth) {
     // Create the swizzler based on the desired color type
     switch (info.colorType()) {
         case kIndex_8_SkColorType:
         case kN32_SkColorType:
         case kRGB_565_SkColorType:
         case kGray_8_SkColorType:
-            return SkSwizzler::CreateSwizzler(SkSwizzler::kBit, ctable, info, opts.fZeroInitialized, 
-                                              this->getInfo());
+            return SkSwizzler::CreateSwizzler(SkSwizzler::kBit, ctable, info, opts.fZeroInitialized,
+                    this->getInfo(), subsetLeft, subsetWidth);
         default:
             return nullptr;
     }
@@ -125,8 +125,9 @@ SkCodec::Result SkWbmpCodec::onGetPixels(const SkImageInfo& info,
 
 
     // Initialize the swizzler
-    SkAutoTDelete<SkSwizzler> swizzler(this->initializeSwizzler(info, ctable, options));
-    if (nullptr == swizzler.get()) {
+    SkAutoTDelete<SkSwizzler> swizzler(this->initializeSwizzler(info, ctable, options, 0,
+            info.width()));
+    if (NULL == swizzler.get()) {
         return kInvalidConversion;
     }
 
@@ -173,7 +174,8 @@ int SkWbmpCodec::onGetScanlines(void* dst, int count, size_t dstRowBytes) {
 }
 
 SkCodec::Result SkWbmpCodec::onStartScanlineDecode(const SkImageInfo& dstInfo,
-        const Options& options, SkPMColor inputColorTable[], int* inputColorCount) {
+        const Options& options, SkPMColor inputColorTable[], int* inputColorCount, int subsetLeft,
+        int subsetWidth) {
     if (options.fSubset) {
         // Subsets are not supported.
         return kUnimplemented;
@@ -197,8 +199,8 @@ SkCodec::Result SkWbmpCodec::onStartScanlineDecode(const SkImageInfo& dstInfo,
     }
 
     // Initialize the swizzler
-    fSwizzler.reset(this->initializeSwizzler(dstInfo,
-            get_color_ptr(fColorTable.get()), options));
+    fSwizzler.reset(this->initializeSwizzler(dstInfo, get_color_ptr(fColorTable.get()), options,
+            subsetLeft, subsetWidth));
     if (nullptr == fSwizzler.get()) {
         return kInvalidConversion;
     }