Focus SkScaledCodec on BitmapRegionDecoder

src/codec/SkScaledCodec.cpp

Index: src/codec/SkScaledCodec.cpp
diff --git a/src/codec/SkScaledCodec.cpp b/src/codec/SkScaledCodec.cpp
index 078a0261a0c392c26e083532cddc358a9ac770b9..fb162939f71412f13089e2e2feaa5e34a3a41c21 100644
--- a/src/codec/SkScaledCodec.cpp
+++ b/src/codec/SkScaledCodec.cpp
@@ -12,22 +12,25 @@
 
 
 SkCodec* SkScaledCodec::NewFromStream(SkStream* stream) {
-    bool isWebp = SkWebpCodec::IsWebp(stream);
-    if (!stream->rewind()) {
-        return nullptr;
-    }
-    if (isWebp) {
-        // Webp codec supports scaling and subsetting natively
-        return SkWebpCodec::NewFromStream(stream);  
-    }
-
     SkAutoTDelete<SkCodec> codec(SkCodec::NewFromStream(stream));
     if (nullptr == codec) {
         return nullptr;
     }
 
-    // wrap in new SkScaledCodec
-    return new SkScaledCodec(codec.detach());
+    switch (codec->getEncodedFormat()) {

[msarett, 2015/10/06 17:38:02]

I'm opposed to this.

I think we've both done a significant amount of refactoring work to make
SkScaledCodec work for all of our image types.  And I think we've made design
decisions based on this goal.

To me, this change feels like we are throwing away work.  I'm fine with
"ignoring" bugs that pop up, but I'm worried this goes too far.

Happy to talk in person.

[scroggo, 2015/10/06 17:52:41]

Ignoring bugs is hard though. If we want to run nanobench and DM, we need to
either make sure that we are not running any images that might break in our
classes where it might not work, or we need to fix (or special case) those bugs.

As an alternative, we could make DM/nanobench ignore anything that is not one of
the three we care about.

And it's not throwing away work. It's reprioritizing. The non-big-three will
still be there when we return to work on them. We should file any outstanding
bugs we are aware of, but leaving them enabled means we may run into them again,
and spend time trying to work around or fix them.

+        case kWEBP_SkEncodedFormat:
+            // Webp codec supports scaling and subsetting natively
+            return codec.detach();
+        case kPNG_SkEncodedFormat:
+        case kJPEG_SkEncodedFormat:
+            // wrap in new SkScaledCodec
+            return new SkScaledCodec(codec.detach());
+        default:
+            // FIXME: SkScaledCodec is temporarily disabled for other formats
+            // while focusing on the formats that are supported by
+            // BitmapRegionDecoder.
+            return nullptr;
+    }
 }
 
 SkCodec* SkScaledCodec::NewFromData(SkData* data) {