Remove superfluous error messages from nanobench

tools/SkBitmapRegionCanvas.cpp

Index: tools/SkBitmapRegionCanvas.cpp
diff --git a/tools/SkBitmapRegionCanvas.cpp b/tools/SkBitmapRegionCanvas.cpp
index c54d936edccb30e4fe204d42c5cb9cf33ff18e27..f8af2dfa493b0b7ce5ed4e1becfc921ed731ed2e 100644
--- a/tools/SkBitmapRegionCanvas.cpp
+++ b/tools/SkBitmapRegionCanvas.cpp
@@ -56,7 +56,6 @@ SkBitmap* SkBitmapRegionCanvas::decodeRegion(int inputX, int inputY,
                                              SkColorType dstColorType) {
     // Reject color types not supported by this method
     if (kIndex_8_SkColorType == dstColorType || kGray_8_SkColorType == dstColorType) {
-        SkDebugf("Error: Color type not supported.\n");
         return nullptr;
     }
 
@@ -115,7 +114,6 @@ SkBitmap* SkBitmapRegionCanvas::decodeRegion(int inputX, int inputY,
     // Start the scanline decoder
     SkCodec::Result r = fDecoder->startScanlineDecode(decodeInfo);
     if (SkCodec::kSuccess != r) {
-        SkDebugf("Error: Could not start scanline decoder.\n");
         return nullptr;
     }