SkPixelSerializer: support indexed pixels

src/image/SkImage.cpp

Index: src/image/SkImage.cpp
diff --git a/src/image/SkImage.cpp b/src/image/SkImage.cpp
index be837f28a8fa8782e16afdc5ed0763c8668c6440..f4227856ca5dc0f7227c120f230a7138dfd692dd 100644
--- a/src/image/SkImage.cpp
+++ b/src/image/SkImage.cpp
@@ -185,9 +185,15 @@ protected:
     bool onUseEncodedData(const void *data, size_t len) override {
         return true;
     }
-
-    SkData* onEncodePixels(const SkImageInfo& info, const void* pixels, size_t rowBytes) override {
-        return SkImageEncoder::EncodeData(info, pixels, rowBytes, SkImageEncoder::kPNG_Type, 100);
+    SkData* onEncode(const SkPixmap& pixmap) override {
+        SkBitmap bm;
+        return bm.installPixels(pixmap.info(),

[scroggo, 2015/12/07 15:57:07]

nit: I think this would be easier to follow if you separate it out into multiple
statements. e.g.

if (!bm.installPixels(...))
  return nullptr;

return SkImageEncoder::EncodeData(...);

Maybe that's just a matter of preference though.

[hal.canary, 2015/12/07 20:25:01]

done

+                                const_cast<void*>(pixmap.addr()),
+                                pixmap.rowBytes(),
+                                pixmap.ctable(),
+                                nullptr, nullptr)
+            ? SkImageEncoder::EncodeData(bm, SkImageEncoder::kPNG_Type, 100)
+            : nullptr;
     }
 };