Improve Color32A_D565 quality at the expense of speed.

src/core/SkBlitRow_D16.cpp

Index: src/core/SkBlitRow_D16.cpp
diff --git a/src/core/SkBlitRow_D16.cpp b/src/core/SkBlitRow_D16.cpp
index 6bf4cea9974f5d4488a65bd6aec532ccbe8096e5..544234d064261aa45104ed4d25df475218339c86 100644
--- a/src/core/SkBlitRow_D16.cpp
+++ b/src/core/SkBlitRow_D16.cpp
@@ -204,27 +204,12 @@ static void S32A_D565_Blend_Dither(uint16_t* SK_RESTRICT dst,
 
 ///////////////////////////////////////////////////////////////////////////////
 
-static uint32_t pmcolor_to_expand16(SkPMColor c) {
-    unsigned r = SkGetPackedR32(c);
-    unsigned g = SkGetPackedG32(c);
-    unsigned b = SkGetPackedB32(c);
-    return (g << 24) | (r << 13) | (b << 2);
-}
-
 static void Color32A_D565(uint16_t dst[], SkPMColor src, int count, int x, int y) {
-    SkASSERT(count > 0);
-    uint32_t src_expand = pmcolor_to_expand16(src);
-    unsigned scale = SkAlpha255To256(0xFF - SkGetPackedA32(src)) >> 3;
-    do {
-        uint32_t dst_expand = SkExpand_rgb_16(*dst) * scale;
-        *dst = SkCompact_rgb_16((src_expand + dst_expand) >> 5);
-        dst += 1;
-    } while (--count != 0);
+    for (int i = 0; i < count; i++) {
+        dst[i] = SkSrcOver32To16(src, dst[i]);
+    }
 }
 
-///////////////////////////////////////////////////////////////////////////////
-///////////////////////////////////////////////////////////////////////////////
-
 static const SkBlitRow::Proc16 gDefault_565_Procs[] = {
     // no dither
     S32_D565_Opaque,