Bug 1628606. Make sure to mark the surface cache entry available before sending the frame complete notification. r=aosmond

We use FRAME_UPDATE and FRAME_COMPLETE notifications to check if we should resolve/reject img.decode promises. But all of the FRAME_UPDATE/FRAME_COMPLETE notifications for image/test/crashtests/1443232-1.gif come before we change the surface cache entry from a placeholder to available. So RequestDecodeForSize returns false and we don't resolve and we don't get anymore notifications.

In this case the DECODE_COMPLETE notifications comes after we mark the surface cache entry as available so checking if we should resolve for DECODE_COMPLETEs would also work, but it seems reasonable for consumers to expect that they can get a frame after getting a FRAME_COMPLETE notification for it.

Differential Revision: https://phabricator.services.mozilla.com/D70312

--HG--
extra : moz-landing-system : lando

image/AnimationSurfaceProvider.cpp

@@ -231,6 +231,16 @@ void AnimationSurfaceProvider::Run() {
       continue;
     }
 
+    // If there is output available we want to change the entry in the surface
+    // cache from a placeholder to an actual surface now before NotifyProgress
+    // call below so that when consumers get the frame complete notification
+    // from the NotifyProgress they can actually get a surface from the surface
+    // cache.
+    bool checkForNewFrameAtYieldResult = false;
+    if (result == LexerResult(Yield::OUTPUT_AVAILABLE)) {
+      checkForNewFrameAtYieldResult = CheckForNewFrameAtYield();
+    }
+
     // Notify for the progress we've made so far.
     if (mImage && mDecoder->HasProgress()) {
       NotifyProgress(WrapNotNull(mImage), WrapNotNull(mDecoder));
@@ -249,7 +259,7 @@ void AnimationSurfaceProvider::Run() {
     // animation may advance even during shutdown, which keeps us decoding, and
     // thus blocking the decode pool during teardown.
     MOZ_ASSERT(result == LexerResult(Yield::OUTPUT_AVAILABLE));
-    if (!CheckForNewFrameAtYield() ||
+    if (!checkForNewFrameAtYieldResult ||
         DecodePool::Singleton()->IsShuttingDown()) {
       return;
     }