Report repetition count in SkCodec

Add a new accessor to retrieve the repetition count.

Remove constants (and corresponding copyright) in SkCodecAnimation.
These may make sense for the calling code, but are not needed here.

kRepetitionCountInfinite corresponds to Blink's kAnimationLoopInfinite.
Move cLoopCountNotSeen to private. It is used to determine whether we
still need to parse. Add a new enum to the parse query - only parse
enough to determine the repetition count.

Unlike Chromium, SkGifCodec does not account for deleting the reader
(which SkGifCodec does not do) or failed decodes.

Add a test.

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2447863002

Review-Url: https://codereview.chromium.org/2447863002

1 files changed, 21 insertions, 2 deletions

diff --git a/include/codec/SkCodec.h b/include/codec/SkCodec.h
index c2519cb840..f2a717c716 100644
--- a/include/codec/SkCodec.h
+++ b/include/codec/SkCodec.h
@@ -607,8 +607,8 @@ public:
     /**
      *  Return info about the frames in the image.
      *
-     *  May require reading through the stream to determine the number of
-     *  frames.
+     *  May require reading through the stream to determine info about the
+     *  frames (including the count).
      *
      *  As such, future decoding calls may require a rewind.
      *
@@ -618,6 +618,21 @@ public:
         return this->onGetFrameInfo();
     }
 
+    static constexpr int kRepetitionCountInfinite = -1;
+
+    /**
+     *  Return the number of times to repeat, if this image is animated.
+     *
+     *  May require reading the stream to find the repetition count.
+     *
+     *  As such, future decoding calls may require a rewind.
+     *
+     *  For single-frame images, this will return 0.
+     */
+    int getRepetitionCount() {
+        return this->onGetRepetitionCount();
+    }
+
 protected:
     /**
      *  Takes ownership of SkStream*
@@ -766,6 +781,10 @@ protected:
         return {};
     }
 
+    virtual int onGetRepetitionCount() {
+        return 0;
+    }
+
     /**
      *  Used for testing with qcms.
      *  FIXME: Remove this when we are done comparing with qcms.