Add SkEncodedFormat, used by SkCodec.

bench/nanobench.cpp

Index: bench/nanobench.cpp
diff --git a/bench/nanobench.cpp b/bench/nanobench.cpp
index 920979cbf9e66c865f2aa21922344ebaccc4e262..fdce3513b8ed360fb59367513cc5c42e3af285e1 100644
--- a/bench/nanobench.cpp
+++ b/bench/nanobench.cpp
@@ -160,7 +160,7 @@ static bool write_canvas_png(SkCanvas* canvas, const SkString& filename) {
         SkDebugf("Can't write %s.\n", filename.c_str());
         return false;
     }
-    if (!SkImageEncoder::EncodeStream(&stream, bmp, SkImageEncoder::kPNG_Type, 100)) {
+    if (!SkImageEncoder::EncodeStream(&stream, bmp, kPNG_SkEncodedFormat, 100)) {
         SkDebugf("Can't encode a PNG.\n");
         return false;
     }