Support RGBA/BGRA swizzles using SkEncodedInfo

include/codec/SkEncodedInfo.h

Index: include/codec/SkEncodedInfo.h
diff --git a/include/codec/SkEncodedInfo.h b/include/codec/SkEncodedInfo.h
index 8c5f51305634865347bb779eb550b7837b88d0f4..5dbdac1c7837c2844e7b4ff786b57a161d02ed8d 100644
--- a/include/codec/SkEncodedInfo.h
+++ b/include/codec/SkEncodedInfo.h
@@ -110,12 +110,10 @@ public:
                 SkASSERT(8 == bitsPerComponent);
                 break;
             case kRGBA_Color:
-                SkASSERT(kOpaque_Alpha != alpha);
                 SkASSERT(bitsPerComponent >= 8);
                 break;
             case kBGRA_Color:
             case kYUVA_Color:
-                SkASSERT(kOpaque_Alpha != alpha);
                 SkASSERT(8 == bitsPerComponent);
                 break;
             default:
@@ -165,6 +163,43 @@ public:
 
     int width() const { return fWidth; }
     int height() const { return fHeight; }
+    Color color() const { return fColor; }
+    Alpha alpha() const { return fAlpha; }
+    uint8_t bitsPerComponent() const { return fBitsPerComponent; }
+
+    SkEncodedInfo makeColor(Color color) const {
+        return SkEncodedInfo::Make(fWidth, fHeight, color, fAlpha, fBitsPerComponent);
+    }
+
+    uint8_t bitsPerPixel() const {
+        switch (fColor) {
+            case kGray_Color:
+                return fBitsPerComponent;
+            case kGrayAlpha_Color:
+                return 2 * fBitsPerComponent;
+            case kPalette_Color:
+                return fBitsPerComponent;
+            case kRGB_Color:
+            case kBGR_Color:
+            case kYUV_Color:
+                return 3 * fBitsPerComponent;
+            case kRGBA_Color:
+            case kBGRA_Color:
+            case kBGRX_Color:
+            case kYUVA_Color:
+            case kInvertedCMYK_Color:
+            case kYCCK_Color:
+                return 4 * fBitsPerComponent;
+            default:
+                SkASSERT(false);
+                return 0;
+        }
+    }
+
+    uint8_t bytesPerPixel() const {
+        SkASSERT(SkIsAlign8(this->bitsPerPixel()));
+        return this->bitsPerPixel() >> 3;
+    }
 
     SkEncodedInfo()
         : fWidth(0)