Fill incomplete images in SkCodec parent class

src/codec/SkScanlineDecoder.cpp

Index: src/codec/SkScanlineDecoder.cpp
diff --git a/src/codec/SkScanlineDecoder.cpp b/src/codec/SkScanlineDecoder.cpp
index e011507f80c316cf445764974bb78aa18104aa47..814a869a1eeae08c0af9025fa04bd9c3b0b4d5b4 100644
--- a/src/codec/SkScanlineDecoder.cpp
+++ b/src/codec/SkScanlineDecoder.cpp
@@ -106,3 +106,20 @@ SkCodec::Result SkScanlineDecoder::start(const SkImageInfo& dstInfo) {
     return this->start(dstInfo, nullptr, nullptr, nullptr);
 }
 
+int SkScanlineDecoder::getY(int srcY) const {
+    //SkASSERT(0 < srcY && srcY < this->dstInfo().height());

[scroggo, 2015/09/25 15:55:06]

Why is this commented out? Should it return some invalid value in that case? I
guess it already will...

[msarett, 2015/10/01 12:44:52]

Hmmm...  Looks like I commented this out instead of fixing it.  It is fixed now.

+    switch (this->getScanlineOrder()) {
+        case kTopDown_SkScanlineOrder:
+            return srcY;
+        case kBottomUp_SkScanlineOrder:
+            return this->dstInfo().height() - srcY - 1;
+        case kOutOfOrder_SkScanlineOrder:
+            return get_output_row_interlaced(srcY, this->dstInfo().height());
+        case kNone_SkScanlineOrder:
+            // When the scanline order is kNone, it is very inefficient to make
+            // more than a single call to getScanlines(), so we should never need
+            // to call getY().
+            SkASSERT(false);
+            return 0;
+    }
+}