Support RGBA/BGRA swizzles using SkEncodedInfo

src/codec/SkCodecPriv.h

Index: src/codec/SkCodecPriv.h
diff --git a/src/codec/SkCodecPriv.h b/src/codec/SkCodecPriv.h
index 2b22922b0c9b158c148b3c0271a0913ccaa2f3bc..8398d5b8e74af219a8639e40defccc405bfec8cd 100644
--- a/src/codec/SkCodecPriv.h
+++ b/src/codec/SkCodecPriv.h
@@ -132,7 +132,8 @@ inline bool conversion_possible(const SkImageInfo& dst, const SkImageInfo& src)
 
     // Check for supported color types
     switch (dst.colorType()) {
-        case kN32_SkColorType:
+        case kRGBA_8888_SkColorType:
+        case kBGRA_8888_SkColorType:
             return true;
         case kRGB_565_SkColorType:
             return kOpaque_SkAlphaType == dst.alphaType();
@@ -275,4 +276,52 @@ inline uint16_t get_endian_short(const uint8_t* data, bool littleEndian) {
     return (data[0] << 8) | (data[1]);
 }
 
+inline SkPMColor premultiply_argb_as_rgba(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
+    if (a != 255) {
+        r = SkMulDiv255Round(r, a);
+        g = SkMulDiv255Round(g, a);
+        b = SkMulDiv255Round(b, a);
+    }
+
+    return SkPackARGB_as_RGBA(a, r, g, b);
+}
+
+inline SkPMColor premultiply_argb_as_bgra(U8CPU a, U8CPU r, U8CPU g, U8CPU b) {
+    if (a != 255) {
+        r = SkMulDiv255Round(r, a);
+        g = SkMulDiv255Round(g, a);
+        b = SkMulDiv255Round(b, a);
+    }
+
+    return SkPackARGB_as_BGRA(a, r, g, b);
+}
+
+inline bool is_rgba(SkColorType colorType) {
+#ifdef SK_PMCOLOR_IS_RGBA
+    return (kBGRA_8888_SkColorType != colorType);
+#else
+    return (kRGBA_8888_SkColorType == colorType);
+#endif
+}
+
+// Method for coverting to a 32 bit pixel.
+typedef uint32_t (*PackColorProc)(U8CPU a, U8CPU r, U8CPU g, U8CPU b);
+
+inline PackColorProc choose_pack_color_proc(bool isPremul, SkColorType colorType) {
+    bool isRGBA = is_rgba(colorType);
+    if (isPremul) {
+        if (isRGBA) {
+            return &premultiply_argb_as_rgba;
+        } else {
+            return &premultiply_argb_as_bgra;
+        }
+    } else {
+        if (isRGBA) {
+            return &SkPackARGB_as_RGBA;
+        } else {
+            return &SkPackARGB_as_BGRA;
+        }
+    }
+}
+
 #endif // SkCodecPriv_DEFINED