use SkBlendMode

skbug.com/5814

Test: compile only
Change-Id: Ibbaff43df1117b2ca77fd8f917f03d88cc476330
(cherry picked from commit 26edbcba8a2ed4cb300e7f87e679e3b73cec2772)
diff --git a/libs/hwui/SkiaShader.cpp b/libs/hwui/SkiaShader.cpp
index 489a306..971c2a3 100644
--- a/libs/hwui/SkiaShader.cpp
+++ b/libs/hwui/SkiaShader.cpp
@@ -309,10 +309,7 @@
         storeCompose(caches, *rec.fShaderB, *rec.fShaderA,
                 transform, textureUnit, description, outData);
     }
-    if (!SkXfermode::AsMode(rec.fMode, &description->shadersMode)) {
-        // TODO: Support other modes.
-        description->shadersMode = SkXfermode::kSrcOver_Mode;
-    }
+    description->shadersMode = rec.fBlendMode;
     return true;
 }