add encodeData() to SkImageEncoder, and add encoding to SkImage

src/image/SkImage.cpp

Index: src/image/SkImage.cpp
diff --git a/src/image/SkImage.cpp b/src/image/SkImage.cpp
index 1169459df638d79d9a4262216f531274b139f402..13af631b2a9689815bfec462ac7864252821560a 100644
--- a/src/image/SkImage.cpp
+++ b/src/image/SkImage.cpp
@@ -9,6 +9,7 @@
 #include "SkImagePriv.h"
 #include "SkBitmap.h"
 #include "SkCanvas.h"
+#include "../images/SkImageEncoder.h"
 
 SK_DEFINE_INST_COUNT(SkImage)
 
@@ -16,6 +17,10 @@ static SkImage_Base* asIB(SkImage* image) {
     return static_cast<SkImage_Base*>(image);
 }
 
+static const SkImage_Base* asIB(const SkImage* image) {
+    return static_cast<const SkImage_Base*>(image);
+}
+
 uint32_t SkImage::NextUniqueID() {
     static int32_t gUniqueID;
 
@@ -35,3 +40,29 @@ void SkImage::draw(SkCanvas* canvas, SkScalar x, SkScalar y,
 GrTexture* SkImage::getTexture() {
     return asIB(this)->onGetTexture();
 }
+
+static const struct {
+    SkImageEncoder::Type    fIE;
+    SkImage::EncodeType     fET;
+} gTable[] = {
+    { SkImageEncoder::kBMP_Type,    SkImage::kBMP_EncodeType  },
+    { SkImageEncoder::kGIF_Type,    SkImage::kGIF_EncodeType  },
+    { SkImageEncoder::kICO_Type,    SkImage::kICO_EncodeType  },
+    { SkImageEncoder::kJPEG_Type,   SkImage::kJPEG_EncodeType },
+    { SkImageEncoder::kPNG_Type,    SkImage::kPNG_EncodeType  },
+    { SkImageEncoder::kWBMP_Type,   SkImage::kWBMP_EncodeType },
+    { SkImageEncoder::kWEBP_Type,   SkImage::kWEBP_EncodeType },
+};
+
+SkData* SkImage::encode(EncodeType et, int quality) const {
+    for (size_t i = 0; i < SK_ARRAY_COUNT(gTable); ++i) {
+        if (gTable[i].fET == et) {
+            SkBitmap bm;
+            if (asIB(this)->getROPixels(&bm)) {
+                return SkImageEncoder::EncodeData(bm, gTable[i].fIE, quality);
+            }
+            break;
+        }
+    }
+    return NULL;
+}