Add subsetting to SkScanlineDecoder

src/codec/SkBmpRLECodec.cpp

Index: src/codec/SkBmpRLECodec.cpp
diff --git a/src/codec/SkBmpRLECodec.cpp b/src/codec/SkBmpRLECodec.cpp
index 26f926a69ddd3842e8076aab74a74331e996d66a..7584880532415fb26b2497ce458f1e3e9e7041b1 100644
--- a/src/codec/SkBmpRLECodec.cpp
+++ b/src/codec/SkBmpRLECodec.cpp
@@ -257,6 +257,12 @@ void SkBmpRLECodec::setRGBPixel(void* dst, size_t dstRowBytes,
 
 SkCodec::Result SkBmpRLECodec::prepareToDecode(const SkImageInfo& dstInfo,
         const SkCodec::Options& options, SkPMColor inputColorPtr[], int* inputColorCount) {
+    // FIXME: Support subsets for scanline decodes.

[msarett, 2015/10/07 22:15:14]

This is broken.  Will fix later.

+    if (options.fSubset) {
+        // Subsets are not supported.
+        return kUnimplemented;
+    }
+
     // Reset fSampleX. If it needs to be a value other than 1, it will get modified by
     // the sampler.
     fSampleX = 1;