Move calls to conversion_possible to SkCodec

Move common code into the base class, so subclasses need not call
conversion_possible.

Use SkEncodedInfo rather than SkImageInfo, and use the proper frame.

API Changes:
- SkAndroidCodec:
  - Add getEncodedInfo(), for SkBitmapRegionCodec
- SkEncodedInfo:
  - Add opaque() helper
- SkBitmapRegionDecoder:
  - Remove unused conversionSupported

(Split off from skia-review.googlesource.com/c/25746)

Bug: skia:5601
Change-Id: If4a40d4b98a3dd0afde2b6058f92315a393a5baf
Reviewed-on: https://skia-review.googlesource.com/34361
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Derek Sollenberger <djsollen@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>

1 files changed, 4 insertions, 13 deletions

diff --git a/src/codec/SkWebpCodec.cpp b/src/codec/SkWebpCodec.cpp
index 94fa175f82..38feb827e4 100644
--- a/src/codec/SkWebpCodec.cpp
+++ b/src/codec/SkWebpCodec.cpp
@@ -398,23 +398,14 @@ static void blend_line(SkColorType dstCT, void* dst,
 
 SkCodec::Result SkWebpCodec::onGetPixels(const SkImageInfo& dstInfo, void* dst, size_t rowBytes,
                                          const Options& options, int* rowsDecodedPtr) {
+    if (!this->initializeColorXform(dstInfo, options.fPremulBehavior)) {
+        return kInvalidConversion;
+    }
+
     const int index = options.fFrameIndex;
     SkASSERT(0 == index || index < fFrameHolder.size());
 
     const auto& srcInfo = this->getInfo();
-    {
-        auto info = srcInfo;
-        if (index > 0) {
-            auto alphaType = alpha_type(fFrameHolder.frame(index)->hasAlpha());
-            info = info.makeAlphaType(alphaType);
-        }
-        if (!conversion_possible(dstInfo, info) ||
-            !this->initializeColorXform(dstInfo, options.fPremulBehavior))
-        {
-            return kInvalidConversion;
-        }
-    }
-
     SkASSERT(0 == index || (!options.fSubset && dstInfo.dimensions() == srcInfo.dimensions()));
 
     WebPDecoderConfig config;