Use an enum for Dart bindings for Skia Paint style

sky/engine/core/painting/PaintingStyle.cpp

Index: sky/engine/core/painting/PaintingStyle.cpp
diff --git a/sky/engine/core/painting/TransferMode.cpp b/sky/engine/core/painting/PaintingStyle.cpp
similarity index 50%
copy from sky/engine/core/painting/TransferMode.cpp
copy to sky/engine/core/painting/PaintingStyle.cpp
index afd168e3d1425408ee6fa6d4d4af299c0cfec1fd..31f39e0287c60198cf32fa6653fd1b0a9bd129d0 100644
--- a/sky/engine/core/painting/TransferMode.cpp
+++ b/sky/engine/core/painting/PaintingStyle.cpp
@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 
 #include "sky/engine/config.h"
-#include "sky/engine/core/painting/TransferMode.h"
+#include "sky/engine/core/painting/PaintingStyle.h"
 
 #include "sky/engine/core/script/dom_dart_state.h"
 #include "sky/engine/tonic/dart_builtin.h"
@@ -13,28 +13,28 @@
 namespace blink {
 
 // If this fails, it's because SkXfermode has changed. We need to change
-// TransferMode.dart to ensure the TransferMode enum is in sync with the C++
+// PaintingStyle.dart to ensure the PaintingStyle enum is in sync with the C++
 // values.
-COMPILE_ASSERT(SkXfermode::kLastMode == 28, Need_to_update_TransferMode_dart);
+COMPILE_ASSERT(SkPaint::kStyleCount == 3, Need_to_update_PaintingStyle_dart);
 
-// Convert dart_mode => SkXfermode::Mode.
-SkXfermode::Mode DartConverter<TransferMode>::FromArgumentsWithNullCheck(
+// Convert dart_style => SkPaint::Style.
+SkPaint::Style DartConverter<PaintingStyle>::FromArgumentsWithNullCheck(
     Dart_NativeArguments args,
     int index,
     Dart_Handle& exception) {
-  SkXfermode::Mode result;
+  SkPaint::Style result;
 
-  Dart_Handle dart_mode = Dart_GetNativeArgument(args, index);
-  DCHECK(!LogIfError(dart_mode));
+  Dart_Handle dart_style = Dart_GetNativeArgument(args, index);
+  DCHECK(!LogIfError(dart_style));
 
   Dart_Handle value =
-      Dart_GetField(dart_mode, DOMDartState::Current()->index_handle());
+      Dart_GetField(dart_style, DOMDartState::Current()->index_handle());
 
-  uint64_t mode = 0;
-  Dart_Handle rv = Dart_IntegerToUint64(value, &mode);
+  uint64_t style = 0;
+  Dart_Handle rv = Dart_IntegerToUint64(value, &style);
   DCHECK(!LogIfError(rv));
 
-  result = static_cast<SkXfermode::Mode>(mode);
+  result = static_cast<SkPaint::Style>(style);
   return result;
 }