Add subsetting to SkScaledCodec

src/codec/SkBmpRLECodec.cpp

Index: src/codec/SkBmpRLECodec.cpp
diff --git a/src/codec/SkBmpRLECodec.cpp b/src/codec/SkBmpRLECodec.cpp
index 20661e1c1cf5f0d0373b19e76d29610b9d87d3f0..4a4abe00972abcac485e2e9d6d5733389d4c4d84 100644
--- a/src/codec/SkBmpRLECodec.cpp
+++ b/src/codec/SkBmpRLECodec.cpp
@@ -200,7 +200,7 @@ size_t SkBmpRLECodec::checkForMoreData() {
 void SkBmpRLECodec::setPixel(void* dst, size_t dstRowBytes,
                              const SkImageInfo& dstInfo, uint32_t x, uint32_t y,
                              uint8_t index) {
-    if (is_coord_necessary(x, fSampleX, dstInfo.width())) {
+    if (is_coord_necessary(x, fSampleX, this->subsetWidth(), this->subsetLeft())) {
         // Set the row
         uint32_t row = this->getDstRow(y, dstInfo.height());
 
@@ -233,7 +233,7 @@ void SkBmpRLECodec::setRGBPixel(void* dst, size_t dstRowBytes,
                                 const SkImageInfo& dstInfo, uint32_t x,
                                 uint32_t y, uint8_t red, uint8_t green,
                                 uint8_t blue) {
-    if (is_coord_necessary(x, fSampleX, dstInfo.width())) {
+    if (is_coord_necessary(x, fSampleX, this->subsetWidth(), this->subsetLeft())) {
         // Set the row
         uint32_t row = this->getDstRow(y, dstInfo.height());
 
@@ -277,7 +277,8 @@ SkCodec::Result SkBmpRLECodec::prepareToDecode(const SkImageInfo& dstInfo,
         return SkCodec::kInvalidConversion;
     }
 
-    SkScaledCodec::ComputeSampleSize(dstInfo, this->getInfo(), &fSampleX, NULL);
+    SkScaledCodec::ComputeSampleSize(dstInfo.dimensions(), this->getInfo().dimensions(), &fSampleX,
+            nullptr);
 
     return SkCodec::kSuccess;
 }
@@ -307,7 +308,8 @@ int SkBmpRLECodec::decodeRows(const SkImageInfo& dstInfo, void* dst, size_t dstR
     // Because of the need for transparent pixels, kN32 is the only color
     // type that makes sense for the destination format.
     SkASSERT(kN32_SkColorType == dstInfo.colorType());
-    SkSwizzler::Fill(dst, dstInfo, dstRowBytes, SK_ColorTRANSPARENT, opts.fZeroInitialized);
+    SkSwizzler::Fill(dst, dstInfo.makeWH(this->subsetWidth(), height), dstRowBytes,
+            SK_ColorTRANSPARENT, opts.fZeroInitialized);
 
     while (true) {
         // If we have reached a row that is beyond the requested height, we have