Bug 1764224 - Don't assert primary frame on printing docs. r=dholbert

ReplicateFixedFrames can create extra frames, but we don't particularly care about this. Differential Revision: https://phabricator.services.mozilla.com/D143471
2022-04-12 21:25:05 +00:00 · 2022-04-12 21:25:05 +00:00 · 85598ec315
--- a/layout/generic/nsVideoFrame.cpp
+++ b/layout/generic/nsVideoFrame.cpp
@ -319,7 +319,10 @@ void nsVideoFrame::Reflow(nsPresContext* aPresContext, ReflowOutput& aMetrics,
                        ReflowChildFlags::Default);

      if (child->GetSize() != oldChildSize) {
-        MOZ_ASSERT(child->IsPrimaryFrame(),
+        // We might find non-primary frames in printing due to
+        // ReplicateFixedFrames, but we don't care about that.
+        MOZ_ASSERT(child->IsPrimaryFrame() ||
+                       PresContext()->IsPrintingOrPrintPreview(),
                   "We only look at the primary frame in ReflowFinished");
        if (!mReflowCallbackPosted) {
          mReflowCallbackPosted = true;
--- a/testing/web-platform/tests/css/css-position/position-fixed-video-controls-print.html
+++ b/testing/web-platform/tests/css/css-position/position-fixed-video-controls-print.html
@ -0,0 +1,7 @@
+<!doctype html>
+<link rel=help href="https://bugzilla.mozilla.org/show_bug.cgi?id=1764224">
+<!-- Really a crashtest but since we can't really have print crashtests, we assert that we print something -->
+<link rel="mismatch" href="/css/reference/blank.html">
+<q style="page-break-after: left"></q>
+<pre>a</pre>
+<audio style="position: fixed" controls="controls">a</audio>