Fill incomplete images in SkCodec parent class

tools/SkBitmapRegionCanvas.cpp

Index: tools/SkBitmapRegionCanvas.cpp
diff --git a/tools/SkBitmapRegionCanvas.cpp b/tools/SkBitmapRegionCanvas.cpp
index 2344d9020f8250299151640034bb4d7fae119744..5f4238ac254d497a114de0369b57a16a5d59cbad 100644
--- a/tools/SkBitmapRegionCanvas.cpp
+++ b/tools/SkBitmapRegionCanvas.cpp
@@ -8,6 +8,7 @@
 #include "SkBitmapRegionCanvas.h"
 #include "SkCanvas.h"
 #include "SkScanlineDecoder.h"
+#include "SkSwizzler.h"
 
 SkBitmapRegionCanvas::SkBitmapRegionCanvas(SkScanlineDecoder* decoder)
     : INHERITED(decoder->getInfo().width(), decoder->getInfo().height())
@@ -129,21 +130,18 @@ SkBitmap* SkBitmapRegionCanvas::decodeRegion(int inputX, int inputY,
     }
 
     // Skip the unneeded rows
-    if (SkCodec::kSuccess != fDecoder->skipScanlines(imageSubsetY)) {
+    if ((uint32_t) imageSubsetY != fDecoder->skipScanlines(imageSubsetY)) {
         SkDebugf("Error: Failed to skip scanlines.\n");
         return nullptr;
     }
 
     // Decode the necessary rows
-    SkCodec::Result result = fDecoder->getScanlines(tmp.getAddr(0, 0), imageSubsetHeight,
-            tmp.rowBytes());
-    switch (result) {
-        case SkCodec::kSuccess:
-        case SkCodec::kIncompleteInput:
-            break;
-        default:
-            SkDebugf("Error: Failed to get scanlines.\n");
-            return nullptr;
+    uint32_t lines = fDecoder->getScanlines(tmp.getAddr(0, 0), imageSubsetHeight, tmp.rowBytes());
+    if (lines != (uint32_t) imageSubsetHeight) {
+        const SkImageInfo fillInfo = tmpInfo.makeWH(tmpInfo.width(), imageSubsetHeight - lines);
+        const uint32_t fillValue = fDecoder->getFillValue(fillInfo);
+        SkSwizzler::Fill(tmp.getAddr(0, lines), fillInfo, tmp.rowBytes(), fillValue,
+                SkCodec::kNo_ZeroInitialized);
     }
 
     // Calculate the size of the output