Do this to allow GetTimeoutForFrame to be called for frames that haven't been decoded yet. Propagate a Maybe result where it makes sense. The remaining callers just bail if they get no return value. Many of them can just assert that they get a return value because they already got the same frame, so the timeout has to be available.
The logic is a little tricky because we have "Forever" timeouts that were sort of treated as error cases.
Instead of copying and concatenating strings into an mDest buffer in
SamplerStackFramePrintfRAII, require callers to keep the string buffer alive
for the duration of the current scope, and store the pointer to the annotation
string in the ProfileEntry. During stackwalking, concatenate the label and the
annotation (separated by a space) and store the resulting string in the
profile buffer.
MozReview-Commit-ID: GEjcLrhhdvb
--HG--
extra : rebase_source : 683749421ee2122805a249cf413e882ee5f33331
For animated images with finite animations we can finish running their animation. At which point we won't call RequestRefresh, and so we will never mark the composited frame as valid (since that is the only place we do that).
To fix this we mark the composited frame as valid when we finish decoding.
But we can do better than that, we can mark the composited frame as valid immediately when we create a new decoded since we are just drawing the final frame from now on.
The SurfaceCache can hold the first frame of a "static" decode as well as the animated frames in two seperate entries. We only care about what happens to the animated frames, so ignore OnSurfaceDiscarded for anything else.
To accomplish this we must pass the SurfaceKey to OnSurfaceDiscarded.
The pref has never been enabled, so this is quite surprising!
It is currently possible (and has been for quite a while) to discard animated images. All we need is the follow sequence of events.
1. Decode an animated image.
2. Move the animated image out of view (so it is not painted).
3. Call canvas.drawImage on the animated image (or anything else that asks for a first frame only decode). This creates a static entry in the surface cache for this first frame in addition to the animated entry. Because it is a static request we will also start a first frame decode. RasterImage::Decode calls SurfaceCache::UnlockEntries
https://dxr.mozilla.org/mozilla-central/rev/4ceb9062ea8f4113bfd1b3536ace4a840a72faa7/image/RasterImage.cpp#1166
and bam, the animated frames are now unlocked (even though the RasterImage, and it's entry in the surface cache is still locked).
4. Switch tabs, open about:memory and minimize memory to actual throw away the animated frames.
5. Switch back to the image tab, scroll the image back into view, it will not animate, it will just show the last composited frame forever.
When we allow animated images to be discarded we still want to track if the image has been fully decoded before, but it would be confusing to say that it is "done decoding" because that sounds like the image is currently decoded, even though it could be discarded at the time.
Carsten "Tomcat" Book
Andrew Osmond
Andrea Marchesini
Timothy Nikkel
Wes Kocher
Eric Rahm
Sebastian Hengst
Markus Stange
Shing Lyu
Ehsan Akhgari
Jonathan Watt
Wei-Cheng Pan
Christoph Kerschbaumer
Iris Hsiao
Manish Goregaokar