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 ba4dc9af8995f2c9093889158a79b3a8990122d5..7d87123e63700c2160a7a5e9b2bddfc30768e0e5 100644
--- a/src/codec/SkCodec_wbmp.cpp
+++ b/src/codec/SkCodec_wbmp.cpp
@@ -70,8 +70,8 @@ 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:
@@ -82,8 +82,8 @@ SkSwizzler* SkWbmpCodec::initializeSwizzler(const SkImageInfo& info,
         default:
             return nullptr;
     }
-    return SkSwizzler::CreateSwizzler(SkSwizzler::kBit, ctable, info,
-                                      opts.fZeroInitialized);
+    return SkSwizzler::CreateSwizzler(SkSwizzler::kBit, ctable, info, opts.fZeroInitialized,
+            subsetLeft, subsetWidth);
 }
 
 bool SkWbmpCodec::readRow(uint8_t* row) {
@@ -121,7 +121,7 @@ SkCodec::Result SkWbmpCodec::onGetPixels(const SkImageInfo& info,
     setup_color_table(info.colorType(), ctable, ctableCount);
 
     // Initialize the swizzler
-    fSwizzler.reset(this->initializeSwizzler(info, ctable, options));
+    fSwizzler.reset(this->initializeSwizzler(info, ctable, options, 0,info.width()));
     if (nullptr == fSwizzler.get()) {
         return kInvalidConversion;
     }
@@ -169,7 +169,8 @@ 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;
@@ -188,8 +189,8 @@ 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;
     }