In some cases, we need to resend missed VideoSegment to new added MediaStreamVideoSink. Append the latest video frames from updateTracks.
MozReview-Commit-ID: 76RFs5fgKpY
--HG--
extra : rebase_source : 1b1e4e60e0653cbf4ef21abf364239514cf171c5
The standard placement new function is declared to not throw, which
means that, per spec, a null check on its result is required. There are
a number of places throughout layout/ where we know that we are passing
non-null pointers to placement new (and receiving them as a return
value), and we are therefore doing useless work performing these null
checks.
Therefore, we should be using an operator new overload that doesn't
require the null check. MFBT has just such an overload, so use that.
nsDisplayListBuilder::Allocate is infallible. Therefore,
nsDisplayListItem::operator new, which calls Allocate to obtain memory,
does not need to declare itself as throwing. And so on for functions
that call nsDisplayListBuilder::Allocate.
operator new overloads that declare that they don't throw exceptions
require a null check on their return value, per the C++ spec. We know
that Servo isn't going to call these functions with null pointers, so
remove the CPP_THROW_NEW annotation and save ourselves some work.
Structs in our style system use an arena-style allocation system,
managed by the presshell to which they belong. All of the relevant
overloads that forward allocation requests to the presshell declare
themselves as CPP_THROW_NEW, which indicates that they do not throw
exceptions. The C++ specification states that operator new overloads
that declare themselves to not throw exceptions require a null check on
their return value. However, the relevant presshell allocation method,
AllocateByObjectID, is infallible and will never return a null pointer.
The callers of all of these methods are therefore doing useless
(compiler-generated) null checks. Let's get rid of those useless checks
by removing the CPP_THROW_NEW annotations. This change declares these
methods will return non-null pointers and throw exceptions in case of
errors--but as we don't use exceptions, and AllocateByObjectID will
abort on OOM, everything works out OK.
The standard placement new function is declared to not throw, which
means that, per spec, a null check on its result is required. There are
a number of places throughout xpcom/ where we know that we are passing
non-null pointers to placement new (and receiving them as a return
value), and we are therefore doing useless work performing these null
checks.
Therefore, we should be using an operator new overload that doesn't
require the null check. MFBT has just such an overload, so use that.
This makes a lot of code more compact, and also avoids some redundant nsresult
checks.
The patch also removes a handful of redundant checks on infallible setters.
--HG--
extra : rebase_source : f82426e7584d0d5cddf7c2524356f0f318fbea7d
