Reporting MediaRawData

gistfile1.md

Reporting for MediaRawData:

Option 1: Report it in nsDocument::DocAddSizeOfExcludingThis (nsINode) HTMLMediaElement -> MediaSource -> SourceBuffer -> TrackBufferManager -> MediaRawData Pro: this should work Con: It would be rather generic under mDOMElementNodesSize

njn suggested expanding the struct to specify HTMLMediaElement specific stuff

• Reporter: https://dxr.mozilla.org/mozilla-central/source/dom/base/nsDocument.cpp#12646
• TracksBufferManager: https://dxr.mozilla.org/mozilla-central/source/dom/media/mediasource/TrackBuffersManager.cpp#1631
• MediaData: https://dxr.mozilla.org/mozilla-central/source/dom/media/MediaData.h#370

Option 2: Unknown, MediaSource might be owned somewhere else https://dxr.mozilla.org/mozilla-central/source/dom/media/MediaDecoder.cpp#445

Async all the things:

1. nsWindowMemoryReporter::CollectReports - This does the reporting of total sizes, passes a sizeof struct into other methods
2. WindowPaths needs to be newed / refcounted
3. Reporting of total sizes needs to be deferred
4. CollectWindowReports returns a promise, ->then decrements pending count
5. CollectWindowReports - This does the reporting of individual windows sizes, calls aWindow->AddSizeOfIncludingThis(&windowSizes);
6. AddSizeOf returns promise ->then does the reporting, increments totals
7. nsGlobalWindow::AddSizeOfIncludingThis - calls mDoc->DocAddSizeOfIncludingThis(aWindowSizes);
8. mDoc->DocAddSizeOfIncludingThis(aWindowSizes) returns promise otherwise create already resolved happy promise
9. nsIDocument::DocAddSizeOfIncludingThis - we care about the subclass implementation nsDocument::DocAddSizeOfExcludingThis(nsWindowSizes* aWindowSizes)
10. Stub out other implementors to return a resolved promise
11. nsDocument::DocAddSizeOfExcludingThis(nsWindowSizes* aWindowSizes) - calls nsINode::SizeOfExcludingThis. These need to take some sort of struct so that they can indicate if they're async
12. Loop through nodes, each returns a promise, ->then will add to the tally
13. Update all INodes to return resolved promise except HTMLMediaElement
14. Return a Promise::All([array of promises])
15. (...7...8...) HTMLMediaElement::SizeOfExcludingThis -> MediaSource::SizeOfIncludingThis -> ad nauseum

Pass in accumulator

struct AsyncSizeAccumulator
{
  MallocSizeOf mSizeOf;
  size_t mSize;
  size_t mPendingRequests;
};

With promises this probably actually isn't necessary.

But we also need some sort of callback mechanism. Promises might be nice:

   Promise MediaSource::DeferredSizeOfIncludingThis(...) {
     Promise deferred = mSourceBuffers->DefferedSizeOfIncludingThis(...);
     return deferred;
  }
  
  Promise TrackBuffersManager::DeferredSizeOfIncludingThis(...) {
    Promise deferred = Dispatch(taskqueue, this, SizeOfExlcudingThisInternal);
    return deferred;
  }